Feb 8 (Reuters) - Switzerland-based software maker Nexthink said on Monday it has raised $180 million from private equity firms Permira, Highland Europe and Index Ventures at a valuation of $1.1 billion, mainly to expand in the United States. Europe has been seeing an increase in funding rounds, with scores of startups being valued at more than $1 billion, and many are expected to list on the public markets before the end of the year. Nexthink, which currently has 1,000 customers, recorded more than $100 million in annual recurring revenue in 2020. The company also said Bruce Chizen, former chief executive of Adobe and senior advisor at Permira, will join its board of directors. (Reporting by Supantha Mukherjee in Stockholm; Editing by Jan Harvey)