Measure 45-46 Chopin Nocturne in E minor

That looks like the Paderewski edition. While it a respectable edition it is edited and some of those edits do not align with urtext editions. The Ekier edition (which is considered to be excellent) does not have the tie which indicates that the tie may be editorial.

However, that does not mean you need to change anything if you like it! Paderewski was a greatly loved Polish pianist and his performances of Chopin were held in high regard. You would just be choosing to maintain a detail that a great performer felt was convincing and satisfying enough to include in their edition (though it is worth noting that by modern standards Panderewski is considered to be on the mannered side). 

In regard to fingering, some editions suggest 43 for the grace notes, likely to help with the legato of the melody line. Either way, you have to make some compromises to get your fingers around the large chords so I would go with whichever works best for you. Holding the B as a tie makes this passage a fair bit trickier, particularly to legato. You would typically play the first chord 1235 and hold the B with 3, move 5-4 (or 5 again quickly depending on span) to the D#, and then resolve the chord to 1 (3) 5.

Great questions!

Edit: I checked some of my other editions once home and while the Ekier does not have the tie, Henle urtext does. None of the commentary from either edition discusses this specific discrepancy. This could mean that there are conflicting sources in which an authoritative version could not be determined. The Ekier commentary does state the following general acknowledgement:

In the sources from which this Nocturne is familiar, additions, and possibly also changes, were undoubtedly made to the performance markings.

You caught an interesting detail!

I was going to add that the Bärenreiter Urtext also has the tie, but I don't know if that is helpful. 

Hi Carlos, great choice learning the piece. I just finished learning it. In my version the B does not have a tie for what it's worth. I think either way it's played sounds fine. Like you said it's hard to tell on the recordings what the artist is doing.

As for the grace notes, I play it using my 5 for the F and E. I slide my 5 down from the F to use the 5 on the E which makes the chord easier to play. 

Hope that helps.

Sam