Can a Nunchuk Replace a Second Wii Remote for Two-Player Wii Sports?

No. You cannot use a Nunchuk in place of a second Wii Remote when playing Wii Sports with two players.

Why It Doesn't Work

• Two Remotes Required: Wii Sports is designed for two Wii Remotes—one per player.
• Nunchuk is an Accessory: The Nunchuk attaches to a Wii Remote to provide additional motion controls (analog stick, two buttons, motion sensing) but cannot function independently as a controller.
• No Single-Controller Mode: The game does not offer a mode where one player uses a Remote and Nunchuk to control both characters.

You will need two Wii Remotes to play Wii Sports with two players.