Under Danish nationality law Nadim could not apply for citizenship until turning 18 years old in 2006.
When citizenship was eventually granted in 2008, FIFA eligibility rules blocked Nadim from playing for Denmark, because she had not yet been resident for the requisite five years after turning 18.
A subsequent challenge from the Danish Football Association (DBU) led to FIFA's legal department making an exception to the rules in Nadim's case.

Nadim immediately became a member of the Denmark national team, making her debut in the 2009 Algarve Cup in a 0–2 defeat by the United States.
In doing so, she became the first naturalised Dane to represent a Denmark senior national football team.
She participated in all three of Denmark's games at UEFA Women's Euro 2009 in Finland.

She was named in national coach Kenneth Heiner-Møller's Denmark squad for UEFA Women's Euro 2013.
In Denmark's opening group match against hosts Sweden Nadim featured as a substitute in an eventful 1–1 draw.

In the UEFA Women's Euro 2017 tournament, she was instrumental in Denmark's advancement, scoring the tying goal in Denmark's eventual 2–1 win over favorites Germany in the knockout stages, and scoring a go-ahead goal in the final, which Denmark ultimately lost to host Netherlands 4–2.
Under Danish nationality law Nadim could not apply for citizenship until turning 18 years old in 2006. When citizenship was eventually granted in 2008, FIFA eligibility rules blocked Nadim from playing for Denmark, because she had not yet been resident for the requisite five years after turning 18. A subsequent challenge from the Danish Football Association (DBU) led to FIFA's legal department making an exception to the rules in Nadim's case.
Nadim immediately became a member of the Denmark national team, making her debut in the 2009 Algarve Cup in a 0–2 defeat by the United States. In doing so, she became the first naturalised Dane to represent a Denmark senior national football team. She participated in all three of Denmark's games at UEFA Women's Euro 2009 in Finland.
She was named in national coach Kenneth Heiner-Møller's Denmark squad for UEFA Women's Euro 2013. In Denmark's opening group match against hosts Sweden Nadim featured as a substitute in an eventful 1–1 draw.
In the UEFA Women's Euro 2017 tournament, she was instrumental in Denmark's advancement, scoring the tying goal in Denmark's eventual 2–1 win over favorites Germany in the knockout stages, and scoring a go-ahead goal in the final, which Denmark ultimately lost to host Netherlands 4–2.
Nadia Nadim