WASHINGTON—With plenty of practice sending coronavirus relief payments to Americans, the federal government should be able to launch the delivery of $1,400 checks almost immediately once Congress finalizes the new aid bill and President Joe Biden signs it, tax experts say. Some Americans might see direct payments as soon as this week if the bill passes the House of Representatives on Tuesday as expected, compared with several weeks’ lag in April 2020. Nearly 160 million households are expected to get payments, the White House estimates. The Treasury Department’s Internal Revenue Service will have new challenges on its hands, though, thanks to the $1.9 trillion relief bill. Incarcerated people, those with non-citizen spouses, and relatives of those who died in 2020 will be eligible for payments. The bill also includes an expanded Child Tax Credit of up to $3,000 per child, paid monthly starting in July, essentially forcing the revenue collector …