Before beginning anything else dice both the Velveeta block and cream cheese block into roughly 1-inch cubes — smaller pieces melt faster and more evenly in the crockpot than large chunks — set aside.
Heat a large skillet over medium-high heat and add ground beef — cook breaking apart with a spatula until completely browned with no pink remaining.
Drain any excess fat from the browned ground beef — leaving too much fat makes the finished dip greasy and can cause cheese to separate.
Sprinkle the entire taco seasoning packet over the drained browned ground beef and stir well to coat every piece of meat evenly.
Add ¾ cup water directly to the seasoned beef in the skillet and stir to combine.
Allow beef to simmer over medium heat for 3–4 minutes stirring occasionally until most of the water has been absorbed and the seasoning has created a slightly saucy well-flavored meat mixture.
Taste the seasoned beef and add salt if needed — add only 1 teaspoon at a time and taste between additions — taco seasoning packet already contains significant salt so additional may not be needed at all.
Remove skillet from heat and transfer the seasoned ground beef to the crockpot.
Add both cans of Rotel tomatoes with all their liquid directly into the crockpot on top of the beef — do not drain the cans.
Add all diced Velveeta cubes and all diced cream cheese cubes on top of the beef and tomatoes — do not stir at this point just layer everything in.
Place lid on crockpot and set to high heat.
Cook on high for 1 hour without opening the lid — opening the lid releases heat and significantly extends the required cooking time.
After 1 hour remove lid and stir everything together thoroughly until completely smooth and uniform — Velveeta cream cheese ground beef and Rotel tomatoes should be fully combined into a single glossy rich dip with no visible unmelted cheese remaining.
If adding fresh cilantro or parsley stir it in now after the cooking is complete — adding herbs before cooking causes them to brown and lose fresh flavor.
Switch crockpot to warm setting to keep dip at perfect temperature throughout the gathering.
Serve directly from the crockpot with tortilla chips alongside — stir occasionally during serving as dip can settle and thicken slightly if left undisturbed.