Nintendo Has a List of Switch 1 Games That Will Be Ready for Switch 2
Any compatibility issues should be solved by launch, or shortly after.

The Switch 2 is nearly here. On June 5, those of us who were lucky enough to snag preorders will start receiving their consoles, and will be able to play new games like Mario Kart World and Donkey Kong Bananza.
Of course, Nintendo's new console isn't only compatible with Switch 2 games. It will play your original Switch games too. The thing is, it isn't as simple as with other backwards compatible consoles: The Switch 2 uses emulation to run original Switch titles, so it isn't playing those games natively. That works for the most part—Nintendo says virtually all first-party Switch games can run on Switch 2 without issue, and the same is true for most "partner" games.
However, some games run into problems with the emulation on Switch 2. Certain titles have issues when starting up (e.g. Wolfenstein II: The New Colossus, Rocket League, and FINAL FANTASY), while others are "playable," but suffer in-game compatibility issues (e.g. ALIEN: ISOLATION, Fall Guys, and Overcooked! All You Can Eat). Nintendo is investigating the issue for these titles, so hopefully they'll all eventually be able to run on Switch 2 as well as they do on the original Switch.
These Switch games are getting updates for Switch 2
In fact, there's already a list of titles with fixes on the way. Nintendo says 49 games with current problems running on Switch 2 will receive updates by system launch or shortly after to fix those issues. (The exception is Fortnite, which is apparently getting a true Switch 2 version rather than an update.)
You can see the full list of games to be updated for Switch 2 below:
112 Operator
ACA NEOGEO ART OF FIGHTING 2
ACA NEOGEO SAMURAI SHODOWN II
ACA NEOGEO THE KING OF FIGHTERS '95
ACA NEOGEO THE KING OF FIGHTERS '96
ACTIVE LIFE Outdoor Challenge
Airhead
Alchemy Garden
Baron: Fur Is Gonna Fly
Batman: The Enemy Within
Beyond the Ice Palace 2
Boot Hill Bounties
Bus Simulator 2023: City Driver
Death Coming
DOOM Eternal
Eggy Party
ENDER MAGNOLIA: Bloom in the Mist
Everspace - Stellar Edition
Fables Mosaic: Snow White and the Seven Dwarfs
Fitness Boxing
Floor Kids
Fortnite (a Switch 2 version is in the works)
FRAMED Collection
Gal Guardians: Demon Purge
Gas Guzzlers Extreme
Guns, Gore and Cannoli
Island Flight Simulator
Korean Drone Flying Tour Jeju Island-1
Mexican Train Dominoes Gold
Monster Energy Supercross - The Official Videogame
MUSYNX
NBA 2K25
Nova-111
OMG Police - Car Chase TV Simulator
Parents Vs Kids
Perseverance: Complete Edition
Pizza Tower
Process of Elimination
Slayin 2
STAR WARS: Dark Forces Remaster
Super Mega Baseball 3
The Jackbox Party Pack
The Jackbox Party Pack 2
Travis Strikes Again: No More Heroes
Victor Vran Overkill Edition
Who Wants to Be a Millionaire?
WolfFang 空牙2001 SkullFang 空牙外伝 Saturn Tribute Boosted
World of Tanks Blitz
Xtreme Sports
Unfortunately, there's no true timeline for when these games will receive their updates. Nintendo's "by launch or shortly after" pledge is quite vague: Will some games be patched? Will most? Which ones? How long after launch is "shortly after?"
The silver lining is that the fixes are on their way. If you have any of these Switch games, or you happen to buy them with your Switch 2, keep an eye out for these updates.