It's not a run-on, and I think it's already phrased decently. A run-on sentence connects two or more separate sentences without anything in between (or with only a comma separating the clauses). Your example sentence is one complete thought, and therefore not a run-on. Wikipedia (linked above) has these examples of run-ons:
A run-on sentence, with no punctuation or conjunction between "gas" and "we":
- My car is out of gas we cannot reach town before dark.
A comma splice, which is considered a run-on sentence in English by some usage experts:
- It is nearly half past five, we cannot reach town before dark.
As to the matter of two and's, there are different "levels" of and. If you regard the words in brackets as one term each, you see that the and's are not connecting sentences; they're connecting nouns:
Growth of the Hispanic population within the US will increase their presence within the workforce, creating new [opportunities and challenges] for [Hispanics and their employers].
It's a good thing to be sensitive to too many and's, and it is considered bad form to connect several independent clauses with and's, even if it's not technically a run-on, and this sentence could get hard to read if I keep using and's to connect separate thoughts, and that's what you need to beware of.