The 29-year-old, competing in her first international sprint regatta, came second in the K1 1,000 event in Montemor-o-Velho.
Broughton said: "I was happy to get out there and put a good race together.
"I'm always a bit slow off the start so I knew I had to stick at my own thing but I knew in the middle it would all settle down."
Great Britain's Lizzie Broughton has won silver at the Canoe Sprint World Cup in Portugal.