American English uses the word 'poppycock' to mean nonsense.
Other words for nonsense include: bolder dash, codswallop, boloney, bollocks, bunkham, clap trap, cobblers, drivel, fiddle sticks, gibberish, guff, hogwash, piffle, tosh, tripe, and twaddle.
The website glossafilia.org can provide more information on this topic.
Finally, here is the third part of this series about English slang words and expressions that most British people know, but which will probably confuse almost everyone else! I started this series in 2019. It's only taken me nearly 4 years to get round to finishing it. Learn loads of slang and culture, plus a bit of British history too.