Yes you can.
The new N46B20 (4 cylinder) engines in the x20i produces the same output @ 125 Kw/ 210Nm, than the M54B22 (6 cylinder) engine found in the E46 320i.
It seems BMW SA are too lazy to update their site, or are unaware of the changes themselves (wouldn't be surprised)
Proof:
Click 320i here on the
BMW Global Site - 125kw/210Nm
And the 320i here on the
BMW SA Site - 110kw / 200Nm
I'd say that's quite an improvement from the previous revision, and quite an impressive output for a 4 Cylinder engine.
With regards to the chip, depending on initial output, you can usually squeeze a bit more than 5 Kw out of a chip.. Especially on an M3.