She returned to England following four years in Italy and South Africa, and her work was shown and positively received at Royal Academy of Arts exhibitions.
After moving to the United States with her husband, Nicholls exhibited her works at the Society of American Artists.
She exhibited her work at the Palace of Fine Arts and the Woman's Building at the 1893 World's Columbian Exposition in Chicago, Illinois.
She received awards in Europe and the United States, including the Chicago World's Fair, a silver medal in Boston in 1885 for Venetian Sunlight, and a gold medal at the American Art Association of New York for Those Evening Bells.
Aside from the Chicago World's Fair, Nicholls won medals at many expositions between 1893 and 1904.
She preferred working in oils and won the highest honors for her oil paintings.
After living in the city for eight years, she was described as "one of New York's best known artists".

Her work is described in The Symposium: A Monthly Literary Magazine:
The first characteristic of this artist's work are strength, accurate knowledge, sure intention, and vigor of expression.
What she has to express she sets forth unhesitatingly with clearness and vim.
There is always great charm in her color; it is pure, vibrating, strong, and yet refined.

— Susan M. Ketcham
Nicholls created illustrations for Howells' Venetian Life in which she captured the "'serene, sunny moods of the sea city,' with its transparent atmosphere and the still heat of its unflinching sun, and the most vivid contrasts are made with a skill that blends without obliterating."
Her works were reproduced in Art Amateur and Art Interchange.
Although she won more awards for her oil paintings, she is best known for her watercolors that were published in these and other publications.
 Other mediums Nicholls employed were pastels, crayons, and wash drawings.

Examples of her paintings of figures are Those Evening Bells, Searching the Scriptures, and The Scarlet Letter.
She made paintings of still life, such as A Rose and Cherries.

Nicholls invented tools and techniques for watercolor paintings, was an innovator in the use of color in her painting of shadows, and was considered "one of the foremost painters of Venetian subjects" in the United States.

Her paintings were shown at the MacDowell Club, which was established by women to exhibit and promote their works.
She was a member of the Woman's Art Club of New York.
Nicholls was made vice-president of the New York Water Color Club and belonged to the American Society of Miniature Painters and the American Water Color Society.
 Nicholls served as co-editor of Palette and Bench.

Nicholls taught art from her 7th Avenue studio in New York, at the Art Students League of New York, William Merritt Chase's Shinnecock School of Art on Long Island, and in towns in the eastern United States.
One of her students was Adele Williams of Richmond, Virginia.
She returned to England following four years in Italy and South Africa, and her work was shown and positively received at Royal Academy of Arts exhibitions. After moving to the United States with her husband, Nicholls exhibited her works at the Society of American Artists. She exhibited her work at the Palace of Fine Arts and the Woman's Building at the 1893 World's Columbian Exposition in Chicago, Illinois. She received awards in Europe and the United States, including the Chicago World's Fair, a silver medal in Boston in 1885 for Venetian Sunlight, and a gold medal at the American Art Association of New York for Those Evening Bells. Aside from the Chicago World's Fair, Nicholls won medals at many expositions between 1893 and 1904. She preferred working in oils and won the highest honors for her oil paintings. After living in the city for eight years, she was described as "one of New York's best known artists".
Her work is described in The Symposium: A Monthly Literary Magazine:
The first characteristic of this artist's work are strength, accurate knowledge, sure intention, and vigor of expression. What she has to express she sets forth unhesitatingly with clearness and vim. There is always great charm in her color; it is pure, vibrating, strong, and yet refined.
— Susan M. Ketcham
Nicholls created illustrations for Howells' Venetian Life in which she captured the "'serene, sunny moods of the sea city,' with its transparent atmosphere and the still heat of its unflinching sun, and the most vivid contrasts are made with a skill that blends without obliterating." Her works were reproduced in Art Amateur and Art Interchange. Although she won more awards for her oil paintings, she is best known for her watercolors that were published in these and other publications.  Other mediums Nicholls employed were pastels, crayons, and wash drawings.
Examples of her paintings of figures are Those Evening Bells, Searching the Scriptures, and The Scarlet Letter. She made paintings of still life, such as A Rose and Cherries.
Nicholls invented tools and techniques for watercolor paintings, was an innovator in the use of color in her painting of shadows, and was considered "one of the foremost painters of Venetian subjects" in the United States.
Her paintings were shown at the MacDowell Club, which was established by women to exhibit and promote their works. She was a member of the Woman's Art Club of New York. Nicholls was made vice-president of the New York Water Color Club and belonged to the American Society of Miniature Painters and the American Water Color Society.  Nicholls served as co-editor of Palette and Bench.
Nicholls taught art from her 7th Avenue studio in New York, at the Art Students League of New York, William Merritt Chase's Shinnecock School of Art on Long Island, and in towns in the eastern United States. One of her students was Adele Williams of Richmond, Virginia.
Rhoda Holmes Nicholls