To cook raw sausage, bake in the oven at 350° for 30 minutes, flip the sausage and cook for another 30 minutes until fully cooked. Cool sausage for about 20 minutes, then slice.
Heat 1 Tablespoon olive oil in a large nonstick skillet with a tight-fitting lid over medium-high heat. Add the sausage slices and cook for a few minutes on each side, until brown, about 5-8 minutes total. Remove to a plate, blot with paper towels to remove any excess oil and set aside.
With a paper towel, wipe the skillet until it is mostly clean. Dice the bell peppers and onion. Heat the remaining Tablespoon of olive oil over medium-high heat. Add the bell peppers, onion, basil, salt, and pepper. Cook until the onion begins to soften and brown, about 3 minutes. Add the cooked rice, garlic, and red pepper flakes, stirring to coat the rice. Cook until fragrant about 30 seconds. Add the chicken stock & canned tomatoes (drained), stirring well. Bring to a boil, stir again, then cover and simmer on low heat for 5 minutes.
Stir in the reserved sausage slices until evenly distributed, then recover the skillet and remove from heat. Let stand 5 minutes, until most of the remaining liquid is absorbed and the rice is tender.