GENEVA — A nationalist party campaigning on fears about mass migration to Europe appeared set Sunday to become the big winner in Swiss legislative elections, according to projections, continuing a shift to the political right for Switzerland.

The anti-immigration Swiss People’s Party appeared set to gain 11 seats and the pro-business Free Democratic Party three in the lower house of Parliament, the National Council, according to the latest figures from RTS, a state-backed broadcaster. Together, the two leading parties of the right were set to hold 99 seats — just one short of half of the 200-seat assembly.

If the rightist parties end up winning control, the result would mark a shift from the success of moderate parties in the last elections four years ago: On Sunday, the biggest parties of the left and center all lost ground or just held even. A projection giving the People’s Party nearly 30 percent of the vote surpassed poll predictions, while the Social Democrats — the country’s second-largest party — unexpectedly lost support.