Opportunize actually is a word
Let's be clear: I don't particularly like opportunize. To me, it smacks of marketing-speak and bad PowerPoints. Also dictionaries don't like this word - I can't find it listed in any.
However, opportunize (or opportunise, if you prefer) makes sense as a word - we all know what it means because it's properly formed according to the rules - and people do use it.
So, my opinion and stylistic prejudice aside, it is a word - it's a functional stand-alone unit of communication. (However, another factor to be borne in mind is that non-native speakers and, say, high-school students are very likely to be 'corrected' if they use words that are anything like opportunize.)
Here's a few samples of opportunize in action:
Still, Achiever conflict-resolutionists should try to opportunize both of the rivals. Improver conflict-resolutionists, however, will reach a different conclusion.
David Kowalewski, Dean Hoover, Dynamic Models of Conflict and Pacification: Dissenters, Officials, and Peacemakers (1995)
On the basis of psychological research, many architects now “harden” and “de-opportunize” public settings to discourage vandalism and graffiti. Some such efforts limit opportunities for vandalism (doorless toilet stalls, tiled walls).
Dennis Coon, John O. Mitterer, Introduction to Psychology: Gateways to Mind and Behavior (2008)
It is the right organism to opportunize the environment which also includes corneal epithelial damage with probable presentation of ligand sites.
Torkel Wadström, Ingvar Eliasson, Ian Holder, Pathogenesis of Wound and Biomaterial-Associated Infections (2012)
Governments may opportunize water issues to promote other political interests. This may especially be relevant in the case of an instrumentalized security discourse.
Philip Jan Schäfer, Human and Water Security in Israel and Jordan (2012)
These examples seem to show my instincts regarding the word were a little off: opportunize's register is definitely formal but more technical or academic rather than business.
There are, of course, valid reasons not to use opportunize, not least that there are better alternatives for your context as opportunize isn't particularly common and, as a technical word, it really isn't suitable for spoken, conversational registers.
For clarity, opportunize means to create opportunities out of.