I like my Bishop, but he has an awful plan to reconstruct our diocese which includes dissolving every single parish and I want to put a stop to it. How can lay Catholics reach the papal nuncio or whoever is above our Bishop in order to veto his actions?
Do lay Catholics have any recourse to override the plans of a diocesan Ordinary?
Yes, lay Catholics may appeal to Rome! It is in Canon Law!
1417 §1. By reason of the primacy of the Roman Pontiff, any member of the faithful is free to bring or introduce his or her own contentious or penal case to the Holy See for adjudication in any grade of a trial and at any stage of the litigation.
You can appeal to the Supreme Pontiff!
Using The Appeal Process
The Church's appeal process belongs to all the faithful and we have a right to use it whenever we are convinced that our rights have been violated, provided that all other means of resolving the issue have been tried first. Then we must remember that the appeal process was not instituted by Christ. Thus like all other legal systems of human invention, the process can be slow and justice does not always triumph in the end. At the same time, in recognition of our responsibilities as members of Christ's Church, if we have to appeal to Rome, we must do so without bitterness, without undue insistence and for marginal issues. - Roman Appeals
Before you go to the Nuncio or the Holy Father through the Nuncio’s attaché case destined for the pope, charity implies that you have already approached your local bishop about the matter in question. In all honesty, do not go over his authority unless you have given him a chance to reply to you demands.
If the faithful feel that there exists some reason that they may not be genuinely heard in a particular situation they may ask the either the Apostolic Nuncio in writing or even better yet write the Holy Father personally through the office of the Apostolic Nuncio to look into your petition or grievance.
In either case, letters should be measured, polite and written in a fraternal and charitable manner. The more signatures the better. Be sure of all the facts you make and trust in God’s help.
If your letter is addressed to the Holy Father himself and you would like it to taken to Rome in the Nuncio’s attaché papers, you must write your letter that is destined for him to be place in an unsealed envelope, because all correspondence that is to be handed over to the pope personally is read by the nuncio at the nunciature. Your letter should be placed in an envelope with a letter to the Nuncio that you wish it to be forwarded to the Holy Father! This is standard papal procedures in such correspondences, so be very prudent how you phrase such appeals.
Please keep copies of all documents and correspondences pertaining to your case in question, they may prove useful later.
You may or may not get a response back, but at least Rome will take a look into it.
In all things, be at peace knowing you done your part.
Do not know how your situation will play out, but I may take a guess at one possibility: The Nuncio will probably talk to your bishop before sending the petition to Rome in order to find a solution.