First, add corn to a skillet with ½ teaspoon of oil. Cook on medium-high until the corn begins to char, about 5-7 minutes. Remove from heat and set aside.
Place a large saucepan over medium-low heat. Add butter and let it melt completely. Once melted, add flour and whisk together to make a roux. Once flour and butter have combined, let it cook until it starts to turn golden brown, about 3-4 minutes. Very slowly whisk in the half and half.
Let the milk mixture heat up until bubbles start to form around the edge. Reduce heat to low. Add about 1/4 cup of the shredded cheese to the mixture and whisky continuously until it completely melts. Repeat with rest of cheese in 1/4-cup increments. Do NOT add more than 1/4 cup of cheese at a time. Otherwise, the cheese will clump up and remain lumpy.
Once the cheese is completely smooth and melted, add diced chiles, 3/4 cup of corn, and spices. Stir together with a wooden spoon. Raise heat back to medium to get the cheese nice and hot. Continue stirring until cheese is hot.
Give cheese a taste. Add salt and pepper, if necessary. Place cheese into a large skillet or other serving dish. Toss the remaining corn with Parmesan cheese and chopped cilantro. Place on top of the queso. Slice fresh jalapeno and place on top of the queso. Serve queso with a bowl of tortilla chips.