Cut the corn tortillas into quarters.
Heat oil in a pan over medium heat.
Fry the tortilla pieces until golden and crispy.
Remove and drain on paper towels.
In the same pan, add the red salsa and bring to a simmer.
Add the crispy tortillas to the salsa, stirring gently to coat.
If using, add shredded chicken and mix well.
Cook for another 2-3 minutes until heated through.
Transfer to serving plates and top with cheese and sour cream.
Garnish with cilantro, onion, and jalapeño slices.