I had the exact same issue. The parents had warned me the 1 year old didn't nap but I scoffed because I always had been able to get the kids to sleep well. The child was used to being breastfed to sleep and I don't think the parents made an effort to establish a proper nap schedule.

. When I was able to get her to sleep, she would wake up after 30 minutes screaming bloody murder. I tried everything over the course of a few months. Eventually I just let her cry it out, though she never went back to sleep and I found it very stressful to hear her. Finally, after a year, I could get her to sleep without issues and have her sleep a solid hour and a half. I found that if I had some cuddle time with her then put her down and caressed her forehead for a few minutes lightly, it was enough to get her dopey and then I would leave. I also had a 2-way monitor in her room so I could shush her and give her occasional reassurance without going in to get her.

It was a year of pure hell getting to this point though.