The phrase "stacks against" implies a situation where something or someone is at a disadvantage. Antonyms for this phrase would be words that indicate favorable circumstances or an advantageous position. Examples of such antonyms include "in favor of," "works for," "supports," and "benefits." When something is in favor of an individual, it means that they have the upper hand, and the odds are in their favor. Similarly, "works for" suggests that everything is going smoothly and aligned towards success. "Supports" and "benefits" also indicate a positive impact on a person, group, or thing. Using these antonyms in place of 'stacks against' would convey a position of strength and positivity.