Is there a way to fix this without replacing the whole part?

[Soliyou]

I repaired many bumpers with 3M or JB plastic weld. If you can extract the broken piece from the channel/clip, you can glue it back together and will be as strong as new.

for the time being, you can pour some hot water on the cover to soften it and push it back into shape so it doesn’t catch on something else.

 

[Mlarv]

The 3m tape I posted early will do it. They use it all the time to put trim pieces on Mustangs and other cars. Your vent shades are done that way now erc. If you put a long piece on it and then use clothes pin clamps to hold it for a few minutes it will work.

 

[lbv150]

Hot glue gun....