Heat a large sauté pan over medium heat. Add oil; add onions, season with salt and pepper and sauté until lightly browned.
Add chiles, and cream, bring to a boil and reduce to a simmer and cook 4 minutes.
Add cheese and potatoes, stirring occasionally, until just heated through. Remove from heat.
Wrap tortillas in plastic wrap or paper towel and heat in microwave on low until warm.