The 21-year-old, who began last season with the club's B team, made 15 league appearances for Sevilla in the latter stages of their La Liga campaign.
"A lot of nice things have happened to me in such a short time so now I must continue to improve and keep working hard," he told Football Espana.
"I'm looking forward to earning a regular place in the side, which is what I want. It's an honour I've been received with open arms and I still can't believe it. I've had some great times with both Sevilla and the national team in the last five months and I've got to get used to it.
"Last year I was on the verge of making the pre-season with the first team, so this year I need to take advantage of this opportunity. I'm still young with much to learn and there is still a lot of work to do."
Sports Mole has identified Moreno as one of five defenders to watch in Spain's top flight in the new campaign.