"Crioulo" (Portuguese) and "criollo" (Spanish) meant originally "native", and became quite usual in the American colonies of Portugal and Spain, to denote whatever originated in the colony itself from what was metropolitan, or otherwise foreign. But from that point their usage diverged.
In New World Spanish, "criollo" ended by denoting the part of local elite already born in the colonies, as opposed to those newly arrived from Spain. I suppose this is the possible context of "noble criollo", though the most common usage is "elite criolla". (It certainly is the context of the quote by García Marquez that Lambie linked — in which it was poorly translated to Portuguese as... "?crioulo nobre").
In Brazil (to the partial exception of Rio Grande do Sul, where the term has a wider meaning, somewhat similar to the original one), in contrast, "crioulo" became almost exclusively associated with slaves or free Blacks born in Brazil, in contrast to those imported from Africa. In this context, it is often a derogatory word (perhaps the closest Portuguese equivalent to "nigger", though it isn't nearly as callous as the "n-word").
Perhaps you are mixing the two languages, one in which "criollo" often refers to a sector of the landed oligarchy — rich and powerful people, and another in which it basically means a Black (and almost by definition, a poor, non-noble) person?
Edit (regarding Rui's new comments on his question):
The phrase «nobre crioulo» was employed by a Portuguese University
Ph.D Professor and it was directed against a colleague of the same
profession and grade. This colleague was born in America Latina.
Brazil is part of Latin America; was the colleague born in Brazil, or in one of the Spanish-speaking countries? If the latter, your professor was deriding his colleague origins among the elite criolla. It would be better if he used the Spanish pronunciation. If the former, then it seems that the Portuguese professor made a mistake, assuming the usage in Brazil is similar to the rest of Latin America, and delivered a quite harsher insult than intended, bordering into racism, especially if the foreign professor has a darker skin.
According to oral sources, which were also unable to refer a written
source, this use would be linked to the way how were identified the
Brazilians nobles, which titles were conferred by Pedro I of Brazil,
when they came to Lisbon.
Not in Brazil that I know.