Regardless of your opinion of maduro, you can still acknowledge that if the head of a sovereign state enacts policies that result in the mass emigration of 8M to neighboring countries, destabilizing all of them [1],[2] in the process, exporting criminal enterprises, any affected head of the affected government certainly has casus belli on said head of state.
The policy of no aggression applies. If a government, thru its actions (or inactions) causes massive aggression and hurt on your own people, then its your *duty* as elected official, to stop it and protect your citizens
Self-defense is literally the most important mandate a government can have.
[1] https://www.reuters.com/world/americas/crime-migration-spect...
[2] https://www.cgdev.org/publication/data-against-fear-what-num...
Amusingly what you described translates to USA actions if you are from a country in the middle east. For example did you know that there are at least 5M emigrants of Afghanistan in Iran?
Not arguing about other nations actions, just a reminder that if you apply many western logic indiscriminately, the resulting bad actors are very different.