In a sauté pan over medium heat, melt the butter. Add the onion, red bell pepper and garlic. Cook, stirring occasionally, until the vegetables are soft, about 3 to 4 minutes. Add the cumin and season with salt and pepper. Remove the vegetables from the heat. Transfer to a large bowl.
Meanwhile, place the cooked chicken in the food processor or a meat grinder. Process for a couple of minutes, or until ground, and add to the onion mixture.
In a small bowl, combine the eggs, chicken broth, and ½ cup of the bread crumbs and mix well. Place the rest of the bread crumbs in separate bowl. Line a baking sheet with parchment paper.
Take small balls from the mixture and form the croquettes. Roll the croquettes in the bread crumbs. Set the croquettes on the prepared sheet. Repeat with the remaining mixture. Place in the fridge to rest for about 3 hours.
In a fry pan over medium-high heat, pour in the oil, enough to cover the croquettes, and heat to 350°F.
Using tongs, carefully place 3 or 4 croquettes in the hot oil (do not crowd the pan) and cook, turning as needed, until golden brown, about 4 minutes. Repeat with the remaining croquettes.