Chile is not a bad country to hitchhike. Especially compared to the south of Argentina, it's really good.
If you tell people you're a foreigner when you ask for a ride, they might ask to see your passport. Just swallow your pride and take the ride.
Chile's Ruta 5 is basically the country's main highway. It goes all the way from north to south. Always try to get into spots where you can talk to people. Especially as a foreigner this will be of great use to get rides.
Victoria is a town in Chile. It is close to Ruta 5 and you will probably want to go to Argentina. There is not a lot of traffic, but if you like to walk, it's great. The landscapes are varying quickly, when getting the short rides from locals. 20 km before the border there is the Aduana. Make sure to quickly get your tramite done and ask around. It's best to get a long ride, since on the Argentinian side of the border hitchhiking will be much more difficult. Beware of the cold, if you're sitting in a pick up truck. There is 4,5 km long tunnel, and it's pretty cold, even in summer.