Digimon Story: Cyber Sleuth - Hacker's Memory

Chaosmon and Chaosmon VA are more complex to get than Hudiemon but just as useful. Like Hudiemon you must get both Digimon on the same playthrough. You can't get Chaosmon then decide to go into NG+ and get Chaosmon VA; you must get both in the original save file OR the NG+ save.
The formula starts with some easy-to-get Digimon, namely Growlmon, Meramon and Birdramon, and there are a number of ways to get them so I'll leave that part to you.
This is going to be a process so I strongly suggest you run 3 PlatinumNumemon with 3 Tactician USBs on each to maximize your EXP gains and minimize the time this will take.
The CAM levels can be forced with the Friendship and Friendship DX items or you can buy a bunch of meat from the DigiLab and feed it to the Digimon in question while they're on the DigiFarm. Remember the higher the grade of meat the more likely the Digimon will reject it so save before you try and if you feel like you've wasted too many just reload your game.
To try and simplify the process I've split it into 4 parts and keep in mind this is by no means the only way to obtain the Digimon needed for the trophy, just the method I used. If you want to have both Chaosmon and Chaosmon VA at the same time you'll need to have a 2nd BanchoLeomon however in my opinion both forms are lackluster. The guide below will start from when you have the Champion level Digimon required and I'll include the minimum stats you need to Digivolve to the next form.

PART 1 - Champion to Ultimate
Digivolve Meramon into Panjyamon when it has these stats:
Level 28+
HP 350+
ATK 75+
SPD 75+

Digivolve Growlmon WarGrowlmon when it has these stats:
Level 30+
ATK 105+
SPD 75+
ABI 20+

Digivolve Birdramon into Garudamon when it has these stats:
Level 30+
ATK 75+
SPD 75+

PART 2 - Ultimate to Mega
Digivolve Panjyamon into BanchoLeomon when it has these stats:
Level 55+
ATK 120+
DEF 130+
ABI 20+

Digivolve WarGrowlmon into Darkdramon when it has these stats:
Level 50+
ATK 150+
DEF 140+
ABI 20+

Digivolve Garudamon into Varodurumon[/b} when it has these stats:
Level 55+
SP 120+
INT 145+
SPD 130+
ABI 40+

PART 3 - Chaosmon
DNA Digivolve BanchoLeomon AND Darkdramon into Chaosmon when they both have these stats:
Level 60+
ATK 255+
ABI 40+
CAM 100%
At this point you should have 1 Chaosmon and 1 Varodurumon. If you want to own both forms at once you'll need a 2nd BanchoLeomon here otherwise you will lose Chaosmon and Darkdramon in exchange for getting Chaosmon VA!

PART 4 - Chaosmon VA
De-Digivolve Chaosmon and choose to keep BanchoLeomon.
DNA Digivolve BanchoLeomon AND Varodurumon into Chaosmon VA when they both have these stats:
Level 60+
ATK 155+
INT 100+
ABI 40+
CAM 100%

As long as you do part 3 and 4 properly AND on the same save file as mentioned in the opening the trophy will unlock.