To activate Neverwinter Nights: Shadows of Undrentide cheats, you first need to hit the tilde [~] key and type in "DebugMode 1" (case sensitive). Then hit the [~] key again and press [Tab]. This should show you a list of the different functions available. Hit [Tab] again to scroll down the list and enter one of the codes below to acheive the desired result. You will see a "Success" message if you entered the cheat correctly. A "Entered Target Mode" message means you must select a character to use the cheat on.

dm_god - God Mode
dm_heal # - Gives you # health
dm_givegold # - Gives the # amount of gold to you
dm_cowsfromhell - Killer flying cows
dm_mylittlepony - Ride a hobby horse
GetLevel # - Raises you an additional # amount of levels
GiveXP # - Sets your Experience to #
SetAge # - Sets your Age to #
SetCON # - Sets your Constitution to #
SetWIS # - Sets your Wisdom to #
SetINT # - Sets your Intelligence to #
SetSTR # - Sets your Strength to #
SetCHA # - Sets your Charisma to #
SetDEX # - Sets your Dexternity to #
SetAppearance # - Change character's race to # (you will be headless until you change back)
SetAttackBase # - Set character's base attack
ModSaveFort - Set character's fortitude save modifier
ModSaveReflex - Set character's reflex save modifier
ModSaveWill - Set character's will save modifier
ModSpellResistance # - Sets your spell resistance modifier to #

Note: If you use a cheat on your character you must load the "nwnplayer.ini" file in the game folder and set the following lines in order to continue in your game:

Single Player Enforce Legal Characters=0
Single Player ItemLevelRestrictions=0