We are going through the exact same thing with DD (she just turned 2), she still really needs a day time nap otherwise she is feral and will fall asleep at 4 oclock sitting up, but she is going till 10 at night playing in her room. I've stopped going in and telling her constantly to get into bed cause the first nights I did this she thought is was a game and it egged her on more. I have found that if I let her go, she generally gets up into bed when she is ready and goes to sleep.

I was told it is a transition stage for dropping day time naps. I'm hoping in a few weeks she is going to make it the extra few hours in the afternoon till bedtime and will drop the nap cause its driving me insane to.