On 15 January 2017, Chiesa appeared to score the match-winner in a 2–1 home win over rivals Juventus, from a Milan Badelj pass; however, the goal was assigned to Badelj, as, following review, the replays did not confirm whether Chiesa had deflected the pass. Later that month, Chiesa extended his contract with Fiorentina until 30 June 2021. On 21 January, he scored his first goal in Serie A in a 3–0 away victory over Chievo. Just eight days later, Chiesa scored his second league goal in a 3–3 home draw against Genoa. On 7 May, he netted the opening goal for Fiorentina in an eventual 2–2 draw against Sassuolo; this being his third goal for the club, and his first in Serie A in nearly four months. The goal came just four minutes after teammate Nikola Kalinić's penalty miss just after the half-hour mark. On 16 September, the following season, Chiesa marked his 30th league appearance for Fiorentina with a goal in the Derby dell'Appennino against Bologna; scoring the opener in the 51st minute of the game, in an eventual 2–1 home win.