The short answer is yes. I found two resources worth investigating if this interests you, but I really don't have the background or the time to pursue them much deeper at the moment:
First there is an essay titled "Chaucer's Italian Inheritance" from The Cambridge Companion to Chaucer.
Exact details have been obscured by the centuries, but it is clear Chaucer visited Italy and it is only natural for him to have become familiar with the intellectual movements there:
Growing up in a mercantile family close by the Thames, Chaucer early
acquired a familiarity with Italian shipmen, traders, and financiers that was put to good use in later professional life; and through his actual visits to Italy, he gained sophisticated, first-hand knowledge of the social and political settings from which the writings of Dante, Boccaccio, and Petrarch had
Later in the essay:
But it is Boccaccio’s example, it would seem, that finally encourages Chaucer to organize a travelling company of tellers under a single narrative structure; fully one-quarter of Chaucer’s tales find analogues in the Decameron.44
From the way these scholars discuss the issue (rather above my level, to be honest), the main points of evidence are:
The great familiarity that Chaucer had with the Italian scene. If you claim Chaucer was ignorant of Boccacio in whole or in part, this fact must be explained as an exception to the general pattern.
The poetic analogues. If it is really true that a quarter of the many tales in Canterbury have analogues in Decameron then surely 'coincidence' is not a satisfying explanation. The simplest assumption to make is that Chaucer had been exposed to Decameron
That '44' is a citation of a rare monograph on the topic:
The Decameron and the Canterbury Tales: New Essays on an Old Question. Investigations of that book would surely be illuminating; there is perhaps no more appropriate text for your question. Good luck tracking it down, though! It's a real shame how many books are lost obscurity before the ink even dries...