Mastering in the same field as my Bachelors I completed my Bachelors in Human Resources Management. Is there any benefit of completing a Masters degree in Human Resources Management, or should I chose another field?
I would say it all depends on where you want to go. Of course, you may not yet be 100% sure yet. I was in a similar situation a few years ago. Here are a few things right off my head that may help you decide:


You probably did a Bachelor thesis or some kind of final work for your undergraduate. What was the closest field to the topic of your thesis? Human Resource Management in general or, say, something more specific like Employee Stress Performance (I just made that up, not sure if that is a valid subfield of HRM)?. Did you like it? Would you have liked a different topic in another subfield better?
What are fields related to HRM? Is it hard to switch from one to the other? Would one require you to learn difficult skills or acquire knowledge in disciplines considered to be difficult (for example math or computing)?. Would you like to acquire those? Would it be beneficial to acquire those skills, even if ending up working in a different field?
Do you have an idol in your field? Some guy who wrote a book about HRM that you like? Your supervisor? Check their CV's and career path? Did they study HRM for a Master's or do they have a very diversified path? Or ask one of your professors for advice.  


Finally, a recommendation: why not wait a year or so and work in your field? Probably you would see much clearer which study would be most beneficial, if you'd like continue to study and you would also have had contact to people who'd just have finished their Master's and could give you some more feedback.