Table: conference_tournament_stats_2
Columns: conference
regular_season_winner
conference_player_of_the_year
conference_tournament
tournament_venue_city
tournament_winner

Question: Who was the regular season winner of the 1999 Big Sky Men's Basketball Tournament was the conference tournament?
SQL: SELECT "regular_season_winner" FROM conference_tournament_stats_2 WHERE "conference_tournament" = '1999 Big Sky Men''s Basketball Tournament'