Preheat your oven to 375°F (190°C) and lightly grease a small oven-safe ramekin with a touch of oil.
In a small mixing bowl, whisk together the egg, 0.25 cup of Greek yogurt, cornmeal, almond flour, and baking powder until a smooth batter forms.
Transfer the cornbread batter into the prepared ramekin and bake for 15 to 18 minutes, or until a toothpick inserted into the center comes out clean.
While the cornbread bakes, heat the olive oil in a medium saucepan over medium heat; add the diced onion and bell pepper, sautéing for 4 minutes until softened.
Slice the hearts of palm into half-inch rounds and add them to the saucepan along with the black beans, kidney beans, tomato puree, chili powder, cumin, nutritional yeast, salt, and pepper.
Reduce the heat to low and let the chili simmer gently for 10 minutes, stirring occasionally to allow the flavors to meld and the sauce to thicken.
Transfer the hot chili to a serving bowl, top with the remaining 0.5 cup of Greek yogurt for a creamy finish, and serve with the warm cornbread on the side.