Time has intrviewed Nintendo president Tatsumi Kimishima and he stated the following about Switch‘s backwards compatibility:
“Switch is not backward compatible with games designed for other systems, and is not currently compatible with controllers designed for other systems,”
“Support for certain controllers may be considered for a future update.“
When questioned about WIiU games eventually ported to Switch, he said that:
“In some cases, games from past systems may be re-released for the Nintendo Switch system as either enhanced or original versions”.
Previously Nintendo confirmed last year that the Switch was not compatible with Wii U or 3DS games.