"As India's economy continues to grow, this partnership will help India meet its energy needs without increasing air pollution and greenhouse gas emissions," Bush said he said as he left Singapore for a summit in Vietnam.
Under the pact, India, a non-signatory of the nuclear Non-Proliferation Treaty (NPT), would get access to long-denied civilian nuclear technology in return for placing its atomic reactors under global safeguards.
The agreement still needs approval by Congress after the two houses reconcile several amendments each made to the legislation. The Senate and the House will meet in December to reconcile the changes.
Congress will also have to consider a US-India accord on technical elements of the deal, including nuclear safeguards. India will split its closely entwined civilian and military nuclear facilities and put some reactors under international inspection.
This must be followed by approvals from the International Atomic Energy Agency and the 45-nation Nuclear Suppliers Group.
A senior government official, who did not wish to be named, said it was a "positive sign that the Senate rejected several 'killer amendments' which would have meant New Delhi could not accept the legislation".
India's military establishment had expressed fears the deal could hurt the defence capability of the country which has fought three wars with nuclear rival Pakistan.
US ambassador to India, David Mulford, was optimistic the deal would become law.
"One has to keep in mind the bill has bipartisan support," Mulford told a TV channel.
The agreement was controversial because the US Congress had to exempt India from requirements of the US Atomic Energy Act, which bans nuclear sales to non-NPT signatories.
US weapons experts had warned such a deal would make it harder to enforce rules against nuclear renegades Iran and North Korea and set a dangerous precedent for other nations with nuclear hopes.