Mix together your seasonings & season both sides of the chicken breasts well. Heat a grill pan over medium to high heat & grill the chicken until done. Set aside.
Cheese Sauce
In a medium sized sauce pot, melt butter over medium heat. Whisk in flour & cook until it begins to just bubble around the edges.
Add in the milk, slowly, whisking to combine as you go. Continue to whisk until mix as heated through. It needs to be hot enough to melt the cheese, but not boiling.
When the mix is hot, start whisking in cheese in small amounts at a time until all of the cheese has been mixed in. Once the cheese is melted, stir in the paprika & cayenne pepper. Season with salt if needed. Serve hot over the chicken.
Rice
In a large saucepan, heat the oil over medium heat. Add the rice, stir to coat in the oil & cook until slightly golden. Stir in the garlic, salt & cumin.
Add the tomato sauce & chicken broth. Turn the heat to medium high heat & bring the mix to a boil.
Once boiling, reduce heat to low, cover with a lid & allow to simmer for 20 to 25 minutes. Remove from heat, toss in freshly chopped cilantro, stir to combine.
Serve under Mexican chicken topped with cheese sauce.