All three words (opening, opportunity and chance) can express the same idea in this sentence. However, when you use the word "opening" it can imply that the other person was talking too much, but finally, there was a space or a gap in the conversation for you to have a TURN. You might not have much to say but you got a TURN to speak. Saying you had an "opportunity" to speak implies you had more than a TURN to speak. It implies you had time to say something of importance or something that was to your ADVANTAGE or to their ADVANTAGE. You might be able to explain something This might be something you have been thinking about for a long time. Now, you have an "opportunity" to explain. Saying you had a "chance" to speak implies that you spoke about something, but you had not planned it. For example, "I had a "chance" to speak about her holiday when I saw her at the bus station". Hope this helps

In the context of the given sentences they have the same meaning and do mean opportunity. They are synonyms of opportunity. An opening is the space between two barriers which someone or something can possibly go through. It's a metaphor for opportunity. A chance, not an chance. It's more of a possibility the outcome is less certain than an opening. The differences in this context are too subtle to make a difference.

the word "question" has one "s" in the middle, not two. His questions [or questioning] left an opening for me to say what I thought. His questions [or questioning] left chance for me to say what I thought. His questions [or questioning] left an opportunity for me to say what I thought. Yes, these three sentences are the same in overall meaning, but can have some very slight differences as described below. Often when the word "opening" is used, is is like the person talked a lot, but paused long enough for me to say something and his questions were directed in such a way as to pull from me what I thought. Chance implies there was not real intention of asking me what I thought, but he paused long enough that I was able to provide my thoughts. Opportunity is closer to opening than chance is. It could be that the person asked for my thoughts and allowed me to provide them (opportunity) or that they paused long enough in their questioning process for me to say what I thought.