The prolific, iconic Horace Silver crafted this one! A DuckDuckGo search on " Nica's dream Pannonica " yields several interesting references to the life of Baroness Pannonica de Koenigswarter (née Rothschild), legendary benefactor and contributor to the jazz scene. And the search should yield a LearnJazzStandards.com link to Nica's Dream, also.
This is likely going to be played in Bbm, I've never run across a recording in any other key. There are at least 3 different ways to do an intro for Nica's Dream. Recordings made at different times used different intros, check out Eddie Palmieri's Latin version. The "Colorado Cookbook" features the descending sequence BbmM7 - AbmM7 - GbM7 - Cm7b5 to F7(alt) punches followed by 7 eighth notes and a drum fill, used by organist Jack McDuff about 1:12 in, and at the end. It's important to note that some recordings vamp on one bar each BbmM7 - AbmM7, but when the melody starts it's two bars BbmM7, two bars AbmM7.
The minor with a major 7 is a difficult chord to sound properly. It basically implies a harmonic minor structure, but the sixth degree of the accompanying chord-scale could very well be sounded as natural 6, and often a minor i chord is written as m6 and M7 is an option. Taste and experience are the best way to gain confidence with this "exotic" harmony. Optionally, a major chord based on 5 of the minor chord will yield a mM9 sound. Other ways to realize mM7 include playing an augmented triad against the root, e.g. C#+5 (C# F A) and the bass plays Bb, and B+5 over Ab in the bass. The mM7 also shows up as a passing chord in the cliche of descending roots in minor: i - i/7 - I/b7 - i/6.
Now, let's think of the Roman numeral approach to Nica's Dream, remembering that Bbm is the relative minor in the key of Db. (Db is the easiest scale on the piano, thumbs on C natural and F natural, extended fingers on the black keys.) This means that the first six measures are parallel mM7 chords: vi for two bars, v two bars, vi two bars. Then measure 7-8 are essentially I7 realized as vm7 - I7. (The second appearance of Abm is not a mM7!) that's the first 8...
The second 8 measures start with a repeat of the harmony used in bars 7-8, Abm7 - Db7 in bars 9-10. The next figure (measures 11-12) needs to be rehearsed in order to be most effective. It's the same rhythm as the F punches of bar 5-6 in the stock descending chord intro, only a different chord on each punch: GbM7 - Db7 - C7+9 (IV - I7 - VII7alt). Once that passage is accomplished there's a sort of a discontinuity as the root stays on C for the move back to the minor i chord, Cm7b5 - F7+9 - Bbm6 comprise measures 13-16, completing the A section with good old vii - III7 - vi. The A section repeats before we get to the bridge - same material, no 1st and 2nd ending.
Letter B, the bridge is in swing tempo, a contrast to the Latin feel of the A section. It's popularly termed a "Latin-Swing sandwich." the 8 bars of the bridge repeat using 1st and 2nd endings to make it a full 16 bars. First two bars are punches on 5 of the key, beats 2 & 4: Ebm9/Ab 2x then Ab7 2x. It then breaks into swing with chords changing every beat, bars 3-4 are arranged, Db Ebm Fm_ Bb7b9_ _ _ Fb7 (E7+4), passing chord beat 4.
Measures 5-6-7 of the bridge are a stock progression, variation on II, ii-V, I. Eb9, Ebm7-Ab7, DbMaj7. The first ending (repeat back to letter B) is biiim7-bVI7, a vanilla Em7-A7 as a surprise interjection before hitting those punches on Ab (measures 1-2) again. After repeating 1 through 7 of the bridge the 2nd ending is a STOP on III7 followed by lead instrument pickups back to letter A.
Yes, there are punches and turn-arounds to rehearse, and the parallel minor with maj 7 chords are tricky. But the horns can relax and count in half time, drums (and percussion) take the faster architectonic levels, and chordal instruments can play accents and concentrate on developing moving lines that answer the lead phrases. A jazz classic, fun to play, good for the audience too because the arranged parts break things up, creating tension and interest.