How old is she? When she's at home, she doesn't nap at all? I don't think it looks like you are lazy, just ask mom if she can try to get her to nap at home for even an hour. Explain to mom that nap time is your break and your time to eat your lunch and get things ready for the afternoon. I can't see any parent thinking that as lazy.
I have a 3.5 year old who doesn't nap at home and mom asked for her to not nap here either as mom says it ruins her bedtime. I disagree but not my child so I said sure. She goes to preschool 2 afternoons a week and that is almost the only time I get a nap time break. However, because she is almost 4 she is fully capable of occupying herself so I do still get a break sort of. There are days she falls asleep and I just let her sleep but tell mom and she pushes bedtime back a bit. So far they haven't complained.
I wouldn't term over no napping but if having the children nap is a must for you than explain this to mom and tell her she has a month (or whatever length of time is appropriate to you) or else she will have to look for an alternate dcp.