Looking at their stuff, I've realized Nintendo's pushed more new IPs in this generation than since they started... here's the list post NES (which obviously had lots of new IPs off the bat).
Notes:
-only Nintendo owned properties count
-listing is in regards to American market specifically (older JP can count)
-no brands based off existing properties or licenses (sports games, Wario, etc)
2nd Generation (1991-1995)
-F-Zero (1991)
-Pilotwings (1991)
-Super Scope 6 (1992)
-Wave Race (1992)
-Battleclash (1992)
-Kirby (1992)
-Star Fox (1993)
-Stunt Race FX (1994)
-Tin Star (1994)
-Uniracers (1994)
-Earthbound (1995)
3rd Generation (1996-2000)
-Cruis'n USA (1996)
-Mole Mania (1997)
-1080° Snowboarding (1998)
-Pokémon (1998)
4th Generation (2001-2005)
-Advance Wars (2001)
-Golden Sun (2001)
-Pikmin (2001)
-Eternal Darkness (2002)
-Animal Crossing (2002)
-Fire Emblem (2003)
-Custom Robo (2004)
-Polarium (2005)
-Geist (2005)
-Nintendogs (2005)
-Trace Memory (2005)
-Screw Breaker (2005)
-Chibi Robo (2005)
-Odama (2005)
Notes:
-only Nintendo owned properties count
-listing is in regards to American market specifically (older JP can count)
-no brands based off existing properties or licenses (sports games, Wario, etc)
2nd Generation (1991-1995)
-F-Zero (1991)
-Pilotwings (1991)
-Super Scope 6 (1992)
-Wave Race (1992)
-Battleclash (1992)
-Kirby (1992)
-Star Fox (1993)
-Stunt Race FX (1994)
-Tin Star (1994)
-Uniracers (1994)
-Earthbound (1995)
3rd Generation (1996-2000)
-Cruis'n USA (1996)
-Mole Mania (1997)
-1080° Snowboarding (1998)
-Pokémon (1998)
4th Generation (2001-2005)
-Advance Wars (2001)
-Golden Sun (2001)
-Pikmin (2001)
-Eternal Darkness (2002)
-Animal Crossing (2002)
-Fire Emblem (2003)
-Custom Robo (2004)
-Polarium (2005)
-Geist (2005)
-Nintendogs (2005)
-Trace Memory (2005)
-Screw Breaker (2005)
-Chibi Robo (2005)
-Odama (2005)