Not really. Corals contribute more than just wastes--many engage in chemical warfare, further complicating the issue. Generally, a tank can be packed with lots of corals and as long as aggression issues are addressed, the tank will have a fairly low bio-load--like plants, corals contain photosynthetic matter and make use of nitrogen in the form of ammonia--but need such low levels that many fish in the tank can cause problems, since many corals are sensitive to detectable levels of ammonia and elevated (higher than 10 ppm) of nitrates.
Some inverts--like snails, crabs, shrimp, worms, etc, are cleaners and actually help process wastes, so are beneficial even though they do produce waste themselves as well.