Like, they've both got the stereotypical awkward Indian engineer who can't talk to women, but SV took a novel approach by not hating him. SV's weird-by-engineering-standards characters are weird for reasons outside of their nerdiness (e.g. Jared's German-language night terrors), BBT just turned Sheldon's nerdiness up to 11. (And created a really nasty autism stereotype in the process.) And so on.
(Can anyone imaging BBT finding a stereotype as obscure as Gilfoyle's occultist thing? Because that's definitely a 'thing', but it's some serious inside baseball.)
If anything, you might argue that the transition from Big Bang to Silicon Valley is a display of the changing position of nerds. More realistically, though, I think they're just aiming at different demographics.