Games like Nonestory P1
Games like Nonestory P1 include Undertale, OneShot, The Witcher 3: Wild Hunt — Remastered, DAVE THE DIVER, and OMORI. We matched them by the tags players give Nonestory P1 on Steam (RPG, Adventure, Funny, Choices Matter, and Multiple Endings): closest matches first, and among equally close ones the better-known games.

Undertale
Shared: Choices Matter · Story Rich · RPG

OneShot
Shared: Story Rich · Indie · Adventure

The Witcher 3: Wild Hunt — Remastered
Shared: RPG · Adventure · Story Rich

DAVE THE DIVER
Shared: Adventure · RPG · Exploration

OMORI
Shared: RPG · Story Rich · Multiple Endings

DELTARUNE
Shared: RPG · Funny · Story Rich

To the Moon
Shared: Story Rich · Adventure · RPG

Back to the Dawn
Shared: RPG · Choices Matter · Story Rich

Finding Paradise
Shared: Adventure · RPG · Story Rich

Legend of Mortal
Shared: RPG · Choices Matter · Multiple Endings

Disco Elysium - The Final Cut
Shared: RPG · Choices Matter · Story Rich

Baldur's Gate 3
Shared: RPG · Choices Matter · Story Rich

Heartbound
Shared: RPG · Adventure · Story Rich

Tainted Grail: The Fall of Avalon
Shared: RPG · Adventure · Exploration

West of Loathing
Shared: RPG · Funny · Adventure

South Park™: The Stick of Truth™
Shared: RPG · Adventure · Funny

Otaku's Adventure
Shared: Funny · Multiple Endings · RPG

Yes, Your Grace
Shared: Choices Matter · RPG · Indie

Detroit: Become Human
Shared: Choices Matter · Multiple Endings · Story Rich

LISA: The Painful
Shared: RPG · Story Rich · Choices Matter

The Witcher 2: Assassins of Kings Enhanced Edition
Shared: RPG · Choices Matter · Story Rich

The Henry Stickmin Collection
Shared: Funny · Multiple Endings · Choices Matter

Dragon Age: Origins - Ultimate Edition
Shared: RPG · Choices Matter · Story Rich

Dungeon Munchies
Shared: Adventure · RPG · Funny