Heat oil in a medium pot over medium-low heat. Add the diced red onions and cook them until they are slightly caramelized, about 5 minutes, stirring occasionally to prevent burning.

Add the rinsed and drained black beans to the pot with onions. Season with paprika, cumin, and kosher salt. Stir well to combine and continue heating for 3 to 4 minutes until the beans are warmed through and aromatic.

While the beans cook, heat a large skillet over high heat. Spray the skillet with oil to prevent sticking, then add the diced chicken breasts. Cook for about 5 minutes, flipping occasionally to brown the chicken evenly and ensure it is cooked through in the center.

Transfer the cooked chicken to a medium bowl and toss it thoroughly with the buffalo sauce, ensuring all pieces are coated.

In serving bowls, spoon 3/4 cup of cooked brown rice. Top each with 1/4 cup of the warm black beans mixture and sprinkle 1/2 cup of shredded cheddar cheese evenly over the beans and rice. Distribute the buffalo chicken over the prepared bases.

If serving immediately, microwave the assembled bowls for about 30 seconds to melt the cheddar cheese for a gooey texture.

Finish each bowl by sprinkling with chopped scallions for a fresh bite and serve hot.

These bowls can be refrigerated for up to 4 days. To reheat, microwave each bowl for about 3 minutes or until heated through, ensuring the cheese melts again.