I've yet to play NWN2 and I want to go a mage like build - what would you guys recommend an OP build for the base campaign? I want to stomp it as I've never played before and looking for help.

Wizard is among the best choices, and there's already a sorcerer who can join fairly early so it makes sense. I would suggest a Necromancer 5 / Arcane Scholar 5 / Red Wizard 10.

Red Wizard requires a human, which is fine cause there aren't really any great alternatives, and prohibits any good alignment.

Attributes: STR 9, DEX 16, CON 12, INT 17, WIS 12, CHA 8. Increase INT every 4 levels, of course.

Skills: Start with concentration, craft armor, craft weapon, lore, and spellcraft. Add appraise once you reach Arcane Scholar and bluff upon becoming a Red Wizard.

Feats: spell focus:evocation, skill focus:concentration, skill focus:spellcraft, empower spell, spell penetration, greater spell penetration, greater spell focus:evocation, craft wondrous item, extend spell, persistent spell, craft magical arms and armor

Spells: Necromancers can't cast divination spells, but that's a very small loss. As a Red Wizard, you won't be able to learn new illusion spells, but can still cast previously known ones. Prioritize learning the following.

1-nightshield, protection from evil, shield, mage armor, lesser orbs, magic missile, color spray
2-resist energy, melf's acid arrow, web, mirror image, false life, bull's strength, cat's grace
3-protection from energy, flame arrow, improved mage armor, fireball, scintillating sphere, haste, greater magic weapon, slow
4-lesser globe of invulnerability, lesser spell breach, stoneskin, evard's black tentacles, greater invisibility
5-vitriolic sphere, cacophonic burst, cone of cold
6-glove of invulnerability, greater spell breach, superior resistance, greater heroism, isaac's greater missile storm, undeath to death, stone to flesh, greater stoneskin
7-energy immunity, delayed blast fireball, mordenkainen's sword
8-mind blank, protection from spells, polar ray, sunburst, horrid wilting
9-mordenkainen's disjunction, meteor swarm, wail of the banshee

Another caster class you may want to consider for a first-time base campaign run is Cleric.

You don't get a companion that adequately fills that role until very late in the campaign and a well-built Cleric is very powerful.

I won't get into specifics, there's over a decade worth of Cleric builds online you can choose depending on what you wish to role-play. Have fun!

Yes, cleric is also top 3 I'd say. You can play them with more of a magic focus with the right choice of domains, but just being a wizard from the start is more straightforward.