As long as i haven't seen her corpse and this hasn't ended I will believe she is alive.
1. Idc what gege has said in interviews, he's a major troll and I don't believe a word he says about what ending jjk will have or anything he says. He could very well just be messing with us
2. I haven't seen her corpse
3. Why would gege put the whole "maybe she could survive" thing into the story only for it to have zero consequences? Like I get that it isn't a guarantee but considering we haven't seen her corpse and that there wasn't a grieving scene I think it's really weird
4. No one has right up said that she is dead, they usually let the sentence fade out a la
"is nobara..?"
*sullen face*
"I see"
Correct me if I'm wrong!!! But I can't remember any verbal confirmation.
The most direct hint at her possible death is that she was shown in one of the recent chapters in the same panel with many other confirmed death characters.

NOBARA MY LOVE PLS BE ALIVE I SWEAR GEGE KILLED HER CUZ SHES TO OP GOD SHE COULD HAVE USED THE LAST FINGER TO HIT HIS SOUL DIRECTLY CALL ME DELUSIONAL BUT GEGE LET NOBARA BE ALIVE AND MY LIFE IS YOURSSSSSSSSSSS