Adjust oven rack to middle position, place 4 individual serving bowls on rack, and heat oven to 200 degrees. Whisk sour cream, 2 tablespoons cilantro, 1 teaspoon lime zest, 1 tablespoon lime juice, and 1/4 teaspoon salt together in bowl; cover and refrigerate until ready to serve. Toss beef with 2 tablespoons water, baking soda, pepper, and 1/4 teaspoon salt in bowl until thoroughly combined; let sit for 20 minutes.
Meanwhile, heat 1 tablespoon oil in 12-inch nonstick skillet over medium heat until shimmering. Add rice and cook, stirring often, until edges of grains begin to turn translucent, about 2 minutes. Add 1/2 teaspoon salt and remaining 2 cups water and bring to boil. Cover; reduce heat to low; and simmer until liquid is absorbed and rice is tender, about 20 minutes.
Off heat, add remaining 1 teaspoon lime zest and remaining 2 tablespoons lime juice and fluff gently with fork to incorporate. Portion rice into warmed serving bowls, cover with aluminum foil, and keep warm in oven.
Heat remaining 1 tablespoon oil in now-empty skillet over medium heat until shimmering. Add onion and bell pepper and cook until just beginning to brown, 5 to 7 minutes. Add beef, breaking up meat with wooden spoon, and cook until no longer pink, 6 to 8 minutes.
Stir in cumin, garlic, and chile powder and cook until fragrant, about 1 minute. Stir in tomato sauce, beans, corn, and remaining 1 teaspoon salt and cook until slightly thickened, about 3 minutes. Spoon chili over rice in bowls; sprinkle with remaining 2 tablespoons cilantro; and serve, passing sour cream–cilantro mixture separately.
