Del Nido confirmed on Monday that they had accepted a two million euro (£1.75million) offer for their home-grown product after the Spain Under-20 international turned down a new contract.
"We made Campana an offer to renew his contract which he didn't accept, he wanted to leave and we accepted that his agent put him on the market and an agreement has been reached with Crystal Palace for two million euros, plus add ons and a percentage of a future transfer," Del Nido was quoted as saying on Sevilla's official website.
"It seems likely that he'll sign today and will travel to the UK tomorrow to have his medical."
Campana has made 20 appearances for Sevilla over the past two seasons after breaking into the first team.
He was also part of the Spain squad that reached the quarter-finals at this summer's FIFA Under-20 World Cup in Turkey.
Del Nido added: "Campana was going to be a star and unfortunately it hasn't worked out here. We've done everything possible to make it happen.
"We want Campana to do well at Crystal Palace because he's one of our products. Hopefully he succeeds in England."