I tried to find it on Youtube, but it is one of those commercials that hasn't survived, I guess.
I found some more information on this page:
Does anyone remember the crying indian
In a moderately interesting conversation of short comments about Native and other stereotypes, Shaggie says: "What about that old Mazola corn oil commercial from the 70s with all the Indians dancing around the fire chanting 'Mazola, Corn Goodness'? That was pretty pathetic. :("
He later says: "After seeing the Mazola corn oil commercial, I think a lot of Indians were crying about the airwaves being polluted with stereotypes."
This commercial would probably go well in Newspaper Rock as an example of a stereotype usage, if only a video copy or something more definite than this could be found.
I looked it up and found that the Indian-Mazola connection is rather famous. In fact, the Mazola Corn Oil ads may be second only to the "crying Indian" environmental ads among commercials featuring Indians.
Native Sons (1998)
The play opens with a beauty pageant host (played by a woman) introducing himself as "George Pepe Flaco Columbus Cartier de Gama Smith" and introducing "from her home in the deep green forest on the other side of the mountain, by the shores of the silver sea" Princess Buttered-on-Both-Sides. Coyote, like all tricksters, is a shape-shifter, and here coyote is in drag. The name "Princess Buttered-on-Both-Sides" is a mocking reference to the stereotypical representation of Indian women as "Princesses" in the world of advertising. Indian Princess types have been used to advertise both Mazola Corn Oil Margarine ("You call it corn, we call it maize," she declares) and "Land O' Lakes Butter." Princess Buttered-on-Both-Sides is thus doubly buttered, and ready, willing and able to service white men sexually and white society passively and servilely. She is a sexual fantasy and a dream of perfect assimilation.
For more on the subject, see the Stereotype of the Month contest.