TGs who do this seem to want someone to say something. It's a type of affirmation that they're making progress in their minds. However, I think it's extremely dangerous career-wise unless you're prepared to come out that day and face the consequences. A lot of TG women fetishize long painted nails. Again, I suggest taking cues from those at work.
Long nails can be cool, or they can be very declasse.
Plus, long nails can draw attention to your giant hands. Express yourself as you wish, but if your goal is to pass, ease up on the nails. There are a kajillion women's magazines with makeup tips. I think Allure and Vogue lead the way as far as useful information. If you buy only one book, buy this one.