Place chopped onion in the bottom of the slow cooker.
Combine seasonings in a small bowl and then rub seasoning mixture all over the roast. (I had some leftover) Place roast over onions, top with chopped peppers,
and then pour the canned tomatoes on top of everything.(I just spooned mine over the roast) Cook on high for 5-6 hours or low for 8-9 hours then shred the meat with two forks. Then serve with desired toppings!
FREEZER MEAL INSTRUCTIONS: Place tomatoes in the bottom of a freezer safe container. Place green peppers on top of tomatoes, then the seasoned roast, then the onions. When ready to cook, invert the container so the tomatoes are on top and cook 1-2 hours longer than the original recipe states. Or make ahead and freeze the cooked meat.