Hammer
As for the aliens...
Well, at the beginning, Daniel referred to the pyramid as being similar to the Mayan or Aztec pyramids in Central America. When he saw the Crystal Skull, he told everyone that his grandfather, Nick, found a similar one in Belize (which is located in Central America also). That indicates that the 'aliens' both Nick and SG-1 saw were most likely of either Aztec or Mayan origin and probably were believed to be the ancient peoples' gods.
It was just a link they threw in - and to leave Nick there with the aliens, that just left an opening for a future storyline where all the questions could be given answers.
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Hammer - DANIELite, JACKette, TEAL'Conian, KAWler, FERling and GM of the Stargate Command RPG
"Colonel O'Neill, what the HELL are you doing?!" "IN THE MIDDLE OF MY BACKSWING??!" -- Hammond and O'Neill, Window Of Opportunity ¦ "I'm telling ya Teal'c, if we don't get out of this soon I'm going to lose it...lose it, it means crazy, nuts, bonzo, to lose control of one's faculties, three fries short of a Happy Meal...WACKO!" -- O'Neill, Window Of Opportunity ¦ "What are you smiling at?" "Nothin'" -- Carter and O'Neill, Window Of Opportunity