In a medium saucepan, heat the stock to simmer.
In a large skillet, cook the corn over medium-high heat along with 2 tablespoons butter, 1 teaspoon salt and ½ teaspoon pepper. Cook, stirring occasionally for 3-5 minutes. Remove to a bowl and set aside.
In the same skillet, melt the remaining 2 tablespoons butter, and the oil. Add the arborio rice, and stir to coat it in the butter and oil. Stir in the remaining salt and pepper.
In increments, add the heated stock to the skillet 1½ - 2 cups at a time, stirring the rice continually until almost all of the stock is absorbed into the rice.
Continue the same process with adding the stock and stirring the rice continually until all of the stock in the stockpot has been added to the risotto. This should take approximately 20-22 minutes for the rice to be tender. *Note - the risotto will be smooth, creamy, and almost doubled in bulk.
Meanwhile, add the mayonnaise to the corn kernels, along with the lime juice. Stir well and add the corn mixture into the risotto. Stir well to combine and heat through.
Stir in the Mexican cheese and ancho chili powder.
To serve, garnish with the cilantro, scallions, and lime wedges.