While "I don't have an opinion" may be the literal translation, the implied meaning is very different from English: It could be "I don't care", but if there is already a suggestion and someone 有意见, what you mean is that that person has a differing opinion – in other words an objection to the suggestion.

I have no objections.

I'm okay with (it, both suggestions, anything, etc.). I've no objections. No comment or Nothing from me.