Let's say you write cc for 150 at $6 ...

And NVDA, for whatever reason rise to 149 after earning. At this time, your cc is already underwater.

You can then do a 

buy 1 150 call

sell 2 160 call

buy 1 170 call

This is a butterfly, which hopefully only cost $1.5. 

In this case, if NVDA rise to 160, you will be selling your shares at 160 instead of 150 (basicall extend your original cc by $10). If NVDA rise above 170, then this butterfly does not help at all and you will still be selling your shares at 150. 

But, what is the chance NVDA can go above 170 by July? Not very high....