Complex sentence: As the Warthogs, the team's mascot was Wally Warthog; with the new nickname, the Dash are holding a name-the-mascot contest for Wally's replacement.
Split into simpler sentences: As the Warthogs, the team's mascot was Wally Warthog. With the new nickname, the Dash held a name-the-mascot contest for Wally's replacement.