The reality TV personality said that she only found out about her co-star's pregnancy and engagement to Jionni LaValle when Polizzi confirmed reports this week.
"I think she was waiting [to tell] because it's bad luck," she told On Air With Ryan Seacrest. "I actually think Nicole is going to be a great mum. She's a very genuine, nice person, her heart is always in the right place.
"She always puts people before her. She's going to love that little meatball... I think this has been her dream. Getting married. Having kids. So, she's really happy and I'm happy for her. I'm going to miss my little partner in crime, but I'm happy for her."
Cortese also admitted that she wasn't sure if Polizzi would return for another season of Jersey Shore.
"Nicole can maybe stop by and we can maybe throw a baby shower," she suggested. "She's doing the spin-off... I don't really know what's going on, but I can't really see her being on the show pregnant. But who knows?"
Jersey Shore star Vinny Guadagnino has also defended Polizzi from accusations that she is not ready for motherhood, saying: "Everyone can talk about how irresponsible she is and how she drinks, but you don't know how she'll be when the baby comes out."