This is the 10276th most frequent Catalan word.
pinzellada
Brushstroke.
In this sentence, 'pinzellada' is used in a literal sense to refer to the stroke of a brush while painting.
Vaig donar una pinzellada final al quadre.
I gave a final brushstroke to the painting.
Here, 'pinzellada' is used metaphorically to signify a subtle addition or nuance, in this case, of nostalgia to the speech.
El seu discurs va tenir una pinzellada de nostalgia.
His speech had a touch of nostalgia.
In this context, 'pinzellada' metaphorically represents an abstract enhancement or small addition that improves the project.