Niceville is a city in Okaloosa County, Florida, United States, located near Eglin Air Force Base on Boggy Bayou that opens into Choctawhatch…Niceville is a city in Okaloosa County, Florida, United States, located near Eglin Air Force Base on Boggy Bayou that opens into Choctawhatchee Bay. It is part of the Crestview-Fort Walton Beach-Destin, Florida Metropolitan Statistical Area. The population was 15,772 at the 2020 census, up from 12,749 at the 2010 census.