Can I save my trip by visiting Nice Sunday to Tuesday?

I'm currently at the Isola2000 as a tag along for a ski trip, however a week ago I messed up my lower back badly. I still risked it, but now I'm here it's very apparent I cannot ski.

I'm thinking of getting a bus into Nice, as my flight back is there on Tuesday.

I'm a bit sad and overwhelmed and I've been scrolling things to do, but I'm honestly lost as to what's good as walking around town isn't super exciting to me as a 26 year old man.

Could anyone suggest some of the best things to eat / see / do / experience in Nice if you only had a couple days there? Awkwardly on Sunday and Monday.