Optional: If you are using chorizo, cook it in the skillet first and remove once fully cooked. Drain most of the excess grease. If you aren't using chorizo omit this step.
If you bought the cheese in blocks, shred 4 oz of each and set aside.
Add butter and garlic to a medium-low heat skillet and mix until fragrant - about 15-20 seconds (don't let the garlic burn).
Add heavy whipping cream and combine.
Slowly add in the monterey jack and white cheddar cheese while combining and ensuring the cheese melts until you add more.
Allow it to heat through and combine as you continue to mix for a couple minutes.
Add in salt and xanthan gum and combine. Mixture will thicken slightly.
Dice jarred jalapeños and toss into cheese and combine.
TIP: let it heat through until it's fully combined and resembles a queso dip - you'll know when it's done! No longer than 10 minutes at this point.
OPTIONAL: At this point you can add the chorizo back in along with diced tomatoes if you opt to use it.