Heat 1 tablespoon cooking oil in a large deep skillet over medium-high heat.
Add the 14-ounce andouille sausage rounds and sauté for 3–5 minutes until mostly browned.
Add the sliced red and green bell peppers and the diced half yellow onion; continue to sauté for about 5 minutes until the vegetables begin to brown and soften.
Stir in the minced garlic and 1 tablespoon Cajun seasoning; sauté 1–2 minutes until fragrant.
Add the 10-ounce can of diced tomatoes with green chilies, 1 cup long-grain white rice, and 1 1/2 cups chicken broth; stir to combine and bring to a boil.
Once boiling, cover the skillet and reduce heat to low; simmer gently, covered, for about 20 minutes until the rice has absorbed the liquid.
Remove the skillet from heat and keep covered for 5 minutes to rest.
Uncover and fluff the rice with a fork to evenly distribute the sausage and vegetables; garnish with sliced green onions and serve.