The "domestic" beer outside the US is Bud. I think it's a national disgrace just like the omnipresent McDonalds and dubbed versions of Baywatch.
I can speak to Valle Nevado. It's far easier to get to than anything in Argentina. Nonstop flights from at least NYC, Miami, Dallas to Santiago. Very modern airport with no hassles other than the cash $62 US dollar entry fee. Even the ATM machines worked perfectly. 8 hours overnight flight to/from Miami. It's a 2+ hour van ride to the resort. It's a very purpose-built modern French ski resort feel. 3 hotels, 2 condos in the complex. The on-piste skiing is nothing special... quite intermediate. There's great off-piste... especially if you ski down to the road below the resort from the surface lift to el Colorado. It interconnects with both el Colorado and La Parva so there are a lot of acres. You can see all the pricing at http://www.vallenevado.com
The comment about flat light applies to all the South American resorts. It's ski-by-braille whenever it's not sunny.
There's no particular need for a tour operator. All you'd need is airline, hotel booking, and airport transportation.
You could save money on lodging by staying at el Colorado or La Parva. If you stayed down in Santiago, you could do the hotel much cheaper but it's 2 hours on a road that closes on powder days.
Portillo has a similar setup to Valle Nevado. Completely self-contained. A couple hours from Santiago. One stop shopping.
Personally, I had a better time in New Zealand. You're not trapped at the resort and you have ultra-friendly Kiwis instead of Chileans who think all Americans have the bank account of Donald Trump. It might have been different if I were fluent in Spanish. I could see doing another NZ trip split between Mt. Hutt, Treble Cone, and Queenstown.