I used 2 boxes of Jiffy 8.5 oz, and it seemed to be just enough. If you like it thick 3 would not be too much. I added chili as was suggested previously. My family quite liked it and they are kind of picky. I thought it was OK, not the best dish I have found on here. It was easy, quick and filling.
I made this tonight, used Fettucini noodles, (did not have anything else). I added all of the ingredients (some were not listed to add) together at the same time. Other than the noodles, I did not change anything. I see no reason to change anything. It was delicious.