In a large, deep pot over medium heat, bring the chicken stock to a rolling boil. Sprinkle in the rice and a pinch of salt, then lower the heat. Cover and steam for 20 minutes.
Gradually add the squash, lima beans, peppers, and corn; stir well. Cover and steam for an additional 20 minutes.
While this mixture cooks, warm the oil in a medium cast-iron skillet over medium heat. Add the garlic and onions, stirring briskly and cooking for about 5 minutes until garlic and onions are just glistening and translucent, but not brown.
Add the remaining seasonings; stir thoroughly and remove from the heat.
Stirring thoroughly, add these ingredients to the steaming rice and balance the seasonings and liquids. Steam for a final 5 minutes, covered. Fluff and serve.