"Nicely" is the adverb here as it describes how the Gorilla Monster is playing with the train. He quickly ate his breakfast. In the sentence above, the adverb 'quickly' appears before the verb 'ate'.

LONDON, April 30 (Reuters) - While it may be tempting to blame the unprecedented power outage that hit the Iberian peninsula this week on the rapid growth of wind and solar power in Spain ...