Using the SAUTE feature on NORMAL, heat the canola oil.
Add the hot dogs and cook until lightly browned. Remove from pan and set aside.
Add ground beef, breaking apart with the back of the spoon. Cook, stirring regularly until no longer pink and begins to render fat.
Add onions, bell peppers, and garlic and cook until softened. Drain the meat of any excess grease.
Add Italian seasoning and salt and pepper to taste.
Return the hot dogs.
Break the uncooked spaghetti in half and place them in the pot on top of the meat in a crisscross pattern to prevent the noodles from sticking together when cooked.
Add spaghetti sauce, diced tomatoes, and water. Sprinkle the sugar. Do NOT stir. Push the noodles down gently so they’ll be submerged in the liquid.
Close the lid of the Instant Pot, setting the valve in the SEALING position.
Cook on HIGH pressure for 7 minutes.
When the 7 minutes are up and the pressure cooker beeps, do a QUICK release. Press CANCEL to turn off the Instant Pot and carefully open the lid.
Let noodles stand for about 1 to 2 minutes and then stir to distribute the sauce.
Ladle on serving plates and garnish with shredded cheese. Serve hot.