Aspas impressed as Spain beat England 2-1 at Wembley in League A Group 4 on Saturday.
The Nations League gives UEFA's 55 member countries competitive games and eliminates often meaningless friendlies.
Star man Luka Modric will come up against many of his club team-mates for the visitors, and worldwide team-mate - and Barcelona player Ivan Rakitic - is happy to have the Real Madrid man on his side. His second strike bounced off the post and the back of goalkeeper Lovre Kalinic, who was awarded an own goal.
It has been an impressive week for Atletico Madrid's Saul Niguez who has scored two goals in as many appearances this worldwide break, continuing to prove just how important he is in Luis Enrique's Spain.
It was also the second time this year that Spain have scored six goals against World Cup runners-up, following their 6-1 win over 2014 finalists Argentina in March.
Then Rodrigo headed Carvajal's cross early in the 2nd half to make it 4-nil.
Spain have now won both of their opening UEFA Nations League games and on this evidence will take some stopping in League A.
"That's why we want to win every match, but we are playing against a Spain team which didn't meet their expectations at the World Cup and are highly motivated now". Spain was coached by Fernando Hierro in Russian Federation after Julen Lopetegui was sacked two days before the tournament. The former Barcelona coach also added defender Jose Luis Gaya and midfielder Dani Ceballos to the starting lineup.
The hosts will need to be in better form against Romelu Lukaku and Eden Hazard than in their last game, the first without influential manager Heimir Hallgromsson, where they were beaten 6-0 by Switzerland.