I don't think there's anything wrong with shade cloth, but in my opinion it should be used as a last resort. I don't know why you would choose to have a light too powerful for your plants, then try to cut it down with a shade cloth unless you have no other option. It's the equivalent of intentionally adding too much salt to your soup, with the added intention of then watering it down to make it more edible. Life happens, of course. You sometimes get a light that's too powerful accidentally (or at a really good price), no doubt. But it's a whole lot easier to move plants further away from the light, and Stefano has more room to move the plants further away. That's what he should do, over a shade cloth. Again, in my opinion.
With the Mars Hydro, at 12" away the light is producing ~800 PPFD. If you move the light 2" further away, it drops to ~600. 4" further than that and it drops to ~400. Nepenthes generally like under 400 PPFD (https://www.carnivero.com/pages/grow-li ... mendations
), so if you can get the light 18" at a minimum, and likely closer to 30-36" away from the light, you should be good. With a 5' grow tent, that's very possible. If not, consider getting a dimmable, or less powerful light. Or a bigger tent. If none of those are possible, then consider a shade cloth.
After significant trial and error, and I'll lean on the error part, from exposing nepenthes to lights, I'll tell you it's better to give them too little light than it is to give them too much light. At too little light (40 PPFD) nepenthes tends not to pitcher and is very slow to grow. But they stay alive. If they aren't pitchering, gradually increase the light. When they appear to be growing well and pitchering, keep them at that distance. Moving them closer will give them more color, but it's a fine line at that point (especially with LED lights) between "color" and "burning".
Each nepenthes also has different requirements. Some like brighter light than others. My hamata likes the darkest corner of my grow area, while my edwardsiana x maxima and ampullaria prefer the brightest spot. Which usually works just fine with LED lights, since the center of the light will have the most light intensity and the corners (sometimes just 1.5' out) will have 30-50% less light intensity. So I put the plants in the edges, and slowly move them in toward the light, finding what they like, before lowering the light.
I hope that helps!