Melt the butter in a large, deep skillet over medium heat. Add the onion, pepper, mushrooms, and garlic. Cook, stirring occasionally, for 8-10 minutes, or until the mushrooms have released their juices and are completely tender and reduced in size.
Turn the heat to medium high. Add the non-dairy milk and 3/4 cup water to the skillet and stir to combine. Bring the mixture to a simmer.
In a small bowl, whisk together the remaining 1/4 cup water, flour, chicken flavored base, and nutritional yeast until you have a smooth slurry. Add this mixture to the simmering vegetables and stir to combine. Turn the heat to low and continue to simmer until the sauce has thickened considerably, 2-3 minutes. Add the chickpeas to the skillet and warm through, about 2 more minutes.
Taste and add salt and freshly ground black pepper as desired. Serve the warm chickpeas and vegetables over cooked brown rice, pasta, toast, or vegan biscuits. Top with chopped green onion tops, chives, or parsley, if desired. Enjoy.