She was challenged by Jackson Carlaw at the final FMQs before the general election.
The SNP, Scottish Tory, Scottish Labour and Scottish Lib Dem leaders clashed on the BBC.
All the Scottish party leaders are out on the campaign trail ahead of Thursday's election.
The debate will be broadcast live on STV at 8pm on Tuesday night.
Nicola Sturgeon, Jackson Carlaw, Richard Leonard and Willie Rennie went head-to-head.