*headsmack*
I'm an idiot. Thank you for reminding about the toolset.
First monster that comes to mind that my 3.5 knowledge tells me should be an easy target is a dragon. The Guardian White Dragon from the Snowglobe kept shrugging off all but my highest rolls. In the Toolset, he shows as having 10 base AC, 10 dex, and a -2 size modifier. My understanding is that NWN ignores size modifiers to touch AC, which should mean he has a mere 10 touch AC. With 10 BAB alone and no negative modifiers, nothing but a roll of natural 1 should miss.
His regular AC is 37. With 10 BAB and a +10 dex modifiers, that would make a roll of 17 or greater a hit. That seems to concur with my experience, though I obviously have to go back and determine the actual numbers.