Anyone have any tips for nap time potty training?

My daughter is 2.5 and fully potty trained as long as she’s awake. Not a single accident for months and can hold her wee for a few hours at a time. Even so, she wets during most 2 hour naps. I’m not worried about nighttime training yet, especially when I can’t figure out this nap time thing! She goes right before a nap, but must sleep so deeply she doesn’t realize she’s going? If she wakes up naturally and has to go, she does. But the sensation of needing to go or being wet doesn’t wake her up. I’ve tried only underwear during naps so she can feel it, but still has accidents. Any advice?