Carter and Congress needed to be on the same page and as you said, he was already a mile down the road without many following.
TBH, history's proven him entirely right on that score.
I don't have enough in-depth knowledge of Congressional leadership and what policy pitched/tweaked how would have gotten them (and the voting public) on side.
Also, an honest account of TMI would've revealed how little danger everyone was in.
What made the public reaction to TMI so hysterical was that nuclear power was a question mark and kept that way from early 1960's on b/c the US military developed it and the AEC went out of its way to minimize and hush up nuclear problems rather than confront them.
The Soviet record was even worse and kept under tighter wraps until Chernobyl made it impossible to hush up.
As to what the US could've done with a saner nuclear energy policy--Paging Asnys!
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Until Asnys weighs in, I'd say the US goes more with more nukes, not less in its quest for energy independence.
Also, if the 1979 energy crisis goes into effect as OTL, Carter gives the oil industry carte blanche to drill, baby, drill and build more refinery capacity as well as push CAFE standards so folks burn less fuel to get around.
Congress could wiegh in and push more mass transit funds, new building standards,tax credits to insulate housing and retrofit more efficient HVAC systems, and other bits to reduce energy consumption would do a lot to help as they did, just much later. More alternative energy R&D would be nice, too.