There's a rodeo going on in the group Nell is part of! ...Although her rodeo attire is simply longer sleeves (as some of the activities can be on the rough side) and a cowgirl hat. Everything else is the same, she dresses appropriately for a rancher (if a little frillier than standard).

Art, Character (c) galacticpink
Harvest Lunatone (c) http://harvest-lunatone.deviantart.com
Story of Seasons (c) Marvelous!
Harvest Moon (c) Natsume
Pokemon (c) Nintendo