Wonderscape Sage's last ability doesn't care if the returned land was nonbasic. It only cares if the land had a nonbasic land type. For example, if you control Omo, Queen of Vesuva and return a Forest with an everything counter on it to your hand to pay the cost of Wonderscape Sage's last ability, you won't discard a card.

Use the subtypes of the returned land as it last existed on the battlefield to determine whether or not you must discard a card. For example, if you return a Copy Land that's a copy of Urza's Cave (a land with the types Urza's and Cave) to your hand to pay the cost of Wonderscape Sage's last ability, you won't discard a card.