Wouldn't it make a whole lot more sense if he were actually...
Same head as BASA El Hombre Nuclear.
No mention of Lex Luthor on the BASA Super Heroes box.
Very similar outfit to El Hombre Nuclear... Turtleneck top, but with shoulder cuffs.
Same black boots. The black boots are unique to El Hombre Nuclear. Though all the BASA boots are similar, El Hombre's has an extra set of ridges.
It even looks like the top is seperated in the front to possibly "reveal" some robot stickers.
Even though there's no masks involved, seems like 1970s BASA's idea of "Evil Hombre Nuclear".