Place chard and a couple of tablespoons of water in a large non-stick skillet and cook, covered, over medium-low heat until chard wilts, about 8 minutes. Stir frequently so chard cooks evenly and doesnt stick. If it begins to stick, add another tablespoon or so of water. Remove wilted chard to a bowl and set aside.
Wipe any flecks of chard out of pan, and using same skillet, heat oil. Add onions and cook over medium heat 3-5 minutes, until they take on some color and begin to soften. Add chiles, stir to combine, then add wilted chard and stir well. Cover and cook on low heat 3-5 minutes more, stirring once or twice to make sure mixture isnt sticking. Cut cream cheese into bits, add to the chard, and cook and stir until it melts into the greens.
Taste and correct seasonings by adding a bit of salt and freshly ground pepper if you like.
Note: You may use authentic Mexican crema, or sour cream, or even a splash of cream, but it works best and tastes best with cream cheese.