Switching health insurance mid-year, can I open and contribute to an HSA even if I opened an FSA earlier this year?

Hi, my SO is switching jobs and with this is switching her health insurance. She opened an FSA and contributed $1,000, she has already used >50% of that amount. In her new job she will be able to pick a plan that gives her the option of opening an HSA. My question is, will she be able to do that in 2023 or does she have to wait until 2024 to be able to do this? Thank you.