Heat up a shallow dutch oven or saute pan. Add some oil.
Fry the Italian sausage on medium until there are mostly no pink areas.
Add in the onions and move the sausage on top of the onions
Once the onion is soft, add in the canned diced tomatoes
Let it come to a boil and turn the heat down.
Cover and let it simmer for about 15 minutes
Once the sausage is cooked through, add in some frozen veggies, cover and let it simmer for about 5 minutes.
Serve with rice.