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