In a medium to large skillet with a fitting lid, add a tablespoon or more of olive oil and the finely diced onion into the pan with the heat set to medium high heat. Allow the onion to sauté until translucent. 

In a separate bowl, add the ground beef to the bowl and with a disposable glove on your hand, use your hand to softly break up and smash the ground beef a little to take away the look of just getting out of the meat grinder.

In a bowl, add the can of Rotel tomatoes and chiles. With an immersion blender, blend the tomatoes and chiles until smooth. (*This step is optional, but preferred.)

Turn the heat off on the skillet with the onions. Add the meat to the skillet, along with the cup of water and the blended Rotel tomatoes. Stir to combine, Put a lid on the skillet, and bring the mixture to a boil. Remove the lid, let it simmer until most all the liquid is out. Stir in the packet of Taco seasonings and add any additional salt if desired. Serve warm.