Bring the milk to a slow boil in medium saucepan over medium heat. Gently boil until reduced to about 1 cup, stirring frequently, about 5 minutes (or a bit longer). Whisk in the cheese. Let cheese melt slowly. Season to taste with salt and pepper.
Char the poplano chiles over flame or under the broiler until blackened. Enclose in a plastic bag for 10 minutes. (No longer than 10 minutes, don't let them steam and turn to mush.) Peel the chiles, leaving the stem intact. Cut a slit lengthwise down the side of each chile; gently remove the seeds. Keep the chiles warm while cooking the eggs. A toaster oven on low heat is perfect for this.
Cook the bacon in a large skillet over medium-high heat until brown and crisp. Remove bacon with a slotted spoon and drain on paper towels. Drain off the drippings from the skillet. Add butter to the skillet and melt over medium heat. Add eggs and stir gently until softly set, about 4 minutes. Mix in the bacon. Season with salt and pepper.
Spoon eggs into chiles through the slit. Arrange 1 stuffed chile on each plate. Spoon warm sauce over. Garnish with serrano pepper strips, cilantro, tortilla chips, sliced tomatoes. Serve the salsa on the side.