This should go without saying. However....

...."NO IS" is not proper English.

Repeat after me:

It is not...

It is not...

It is not...

It is not...

It is not...

It is not...

It is not...

I'm not usually this sarcastic about class notes, but, c'mon, guys....this is basic. "NO IS" is totally Spanglish. It doesn't matter how many times you say it -- it will never be correct.