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