Baby hates covers

So it is getting a little chilly but this boy won't take a cover. All I want his to cover his feet so he doesn't get cold. It is also not cold enough for a sleeping sack. Now do I want him to sleep in socks or pants. I usually just have him in a onesie and diaper. How are your babies sleeping? How do I make sure his lower body doesn't get too cold?

Update: Thank you all for the tips