Coat the Beef: Whisk 3 tablespoons all-purpose flour with 2 teaspoons chili powder, 1 teaspoon ground cumin, 1 teaspoon kosher salt, 1 teaspoon smoked paprika, 1 teaspoon garlic powder, 1 teaspoon onion powder, ½ teaspoon dried oregano, and ¼ teaspoon freshly cracked black pepper in a medium bowl. Toss 1 ½ lbs beef stew meat in the mixture until every piece is thoroughly coated.
Sear the Meat: Heat 2 tablespoons olive oil in a heavy skillet over medium-high heat (or use the SEAR/SAUTÉ function on High if using a Ninja Foodi PossibleCooker PRO). Working in batches if needed, sear the seasoned beef chunks for 2 to 3 minutes per side until browned, then transfer to your slow cooker.
Sauté Aromatics: Reduce the skillet heat to medium. Add 1 large white onion, 1 green bell pepper, and 4 minced garlic cloves. Sauté for 2 minutes, using a wooden spoon to scrape up the flavorful browned bits from the bottom of the pan, then transfer the veggies to the crockpot.
Slow Cook: Pour 1 can (15 oz) tomato sauce, 1 can (10 oz) Ro*Tel diced tomatoes with green chilies (with its juices), and ¼ teaspoon liquid smoke into the slow cooker. Stir gently, cover with the lid, and cook on LOW for 6 to 8 hours (recommended) or on HIGH for 3.5 to 4 hours until the beef is melt-in-your-mouth tender.
Finish and Serve: Turn off the heat and stir in 1 tablespoon fresh lime juice. Serve hot over a bed of fluffy rice or with warm flour tortillas.