Here is the full list of all 45 Digimon World: Next Order achievements.
First time fleeing from a fight
Maxed out Tamer level
Acquired over 1,000,000 bits
Defeated Armageddemon
Partner reached age 20
Cleared Chapter Four
Cleared Chapter Three
Won 300 battles
Cleared Chapter Two
Prosperity at level 100
First camp
First Colosseum victory
Inflicted 9,999 damage in one attack
Prosperity at level 50
Cleared Chapter One
Acquired over 100,000 bits
First Digivolution to Mega
First Digivolution to Ultimate
All skills for Partner Digimon at 1,000
First fish caught
Inflicted 1,000 damage in one attack
First Digivolution to Champion
Maximum value for DigiFriend
First training mistake
First Tamer level
First king-sized foe defeated
Maximum value for Bond
First materials acquired
First food ingredient item picked up
Prosperity at level 1
Finished a battle with no damage
First Digivolution to Rookie
First training
First Partner Digimon reborn as DigiEgg
Acquired all achievements
Raised 50 types of Digimon
First DNA Digivolution
Maxed out grades on all facilities as builder
Won all Colosseum competitions
Raised 100 types of Digimon
Completed DigiCards
Partner reborn as DigiEgg 20 times
Cleared all extra dungeons
Raised 200 types of Digimon
Maxed out city's Prosperity