A chance is something you're able to do or achieve. It also means that something could happen in the future.
Ex: When the government told me they would pay for me to travel to Australia to complete a degree, I was so excited. It was my chance to travel and study at the same time!
Ex: There's a good chance that Phillip has already seen the film showing at the cinema tonight. He goes to the cinema almost every day.
Chance can also mean something is based entirely on luck or good fortune when used in phrases like game of chance or left up to chance.
Ex: When I go to the casino, I prefer to play games of chance, like dice, slot machines, or roulette. I'm very lucky and I win quite often!
Ex: Mary is leaving this decision to chance. If the coin flips on one side, she will go to the right, but if it flips on the other side, she will go to the left.
An opportunity is a time or setting that allows someone to do something.
Ex: There will be many opportunities to talk during this English course. The teacher includes conversation practice with every lesson.
An equal opportunity (or opportunities) employer is a business or company who has agreed to allow everyone (regardless of gender, race, age, religion, etc.) the same chances to be hired and succeed. These employers base their decisions on someone's work and experience rather than their appearance.
Ex: Make sure to include in the job posting that we are an equal opportunity employer. I want everyone who is qualified to apply to this position, regardless of their race.
Ex: Rwanda is glad that she lives in a time of equal opportunity employers. Fifty years ago, she might not have even been hired, let alone been promoted to Vice President of the company.