Supposedly ChatGPT is based on "GPT-3.5". When GPT-3 came out in 2020, it wasn't really good at rhyming words. It could do okay-but-not-great blank verse. There are some examples of 2020-era GPT-3 poetry here:
https://www.gwern.net/GPT-3#miscellaneous-poetry
ChatGPT is way better at poetry than the original GPT-3.