Firstly, how many times have you washed them? With those, they'll take about 10 washes to reach max absorbency, so you might get a leak tonight. Nina is a big wetter too, and I found I couldn't put a BBH on her overnight until I'd washed them quite a few times.
Now, to answer your question, I'm not really sure. I wouldn't think it would be a problem tucking them in?