A quality layer or grower feed with oyster shell offered in a separate container is what she needs. A friend would be nice as well, since chickens thrive in a flock.
Oh.....so she is your only chicken? She may not know where to lay.....do you have a nesting box set up? Putting golf balls or fake eggs where you want her to lay will help. How is the natural lighting in your basement?
Welcome to our FUNomenal community!
Do you free range? If so, she might be already....in a hidden nest somewhere. If not, any time now. I have late layers too....waiting is the hardest part!