Digimon World Dusk: Dark Quest: Find the Pink Lipstick.

First of all, go talk to Myotismon in Dark Center to start the quest. Then go to the Dark Plaza to find Kokomon. She will tell you to go to Chip Forest to get her lipstick back.

Go there and move to southwest until reach to the area with the door. Don't go thru the door, instead take the path to northwest to the dark area. Go to the left and up a bit, then you will find Nanimon. Save the game and talk to Nanimon.

Nanimon 
HP: 2100~
EXP: 156 Machine
Bit: 160 bits.
Beware with his Soulful Kick, it hits almost half of Digimon's HP.

Once you get Pink Lipstick, return to the city and give it to Kokomon and get 150 Tamer Points, 6590 bits and a Poison Core a.

*You can find Nanimon in Chip Forest after you have done this quest.