This is perhaps the most beloved of Chopin's nocturnes, featuring a deeply songful melody that evokes a serene night atmosphere. Its distinctive character comes from the interplay between the bel canto melody and the steady, swaying left-hand accompaniment.
The primary challenge is balancing the two-against-three polyrhythm while maintaining a seamless, vocal quality in the melody.
Comparable difficulty and character — good candidates for what to learn next.
Nocturne in E-flat major, No. 2 is rated Henle level 5 of 9 — late intermediate repertoire, roughly ABRSM grades 6–7. In the RCM system it corresponds to about level 8.
You should be comfortable at Henle level 5 — meaning you can already play level 4–5 pieces cleanly. Learning it one level early is possible as a stretch piece, but more than that usually leads to months of frustration.
A typical performance of Nocturne in E-flat major, No. 2 lasts about 4.5 minutes.
Nocturne in E-flat major, No. 2 is available as free public-domain sheet music on IMSLP — the score is linked directly from this page.
Pieces at a comparable difficulty and character include Étude in E major, No. 3 by Frédéric Chopin, Prelude in D-flat major, No. 15 by Frédéric Chopin, Nocturne in B-flat minor, No. 1 by Frédéric Chopin — see the full similar-pieces list on this page.