I found 5 newpaper articles with mention of him- I would be happy to send them to you.
1883-5-1 Helena Independent
Indictments of county officials- defrauding county- John Chinnick name on list- he indicted for unlawful detention of books.
1883-7-27 Helena Independent
John Chinnick shot through bowels by Winchester rifle. Various rumors- he says he shot himself accidently- others say his wife did it- others say gang shot him. He was leasee of Cosmopolitan theatre which burned to ground last Sunday morning.
1883-7-29 Helena Independent
Headline-Miles City Reign of Terror-
fire, lynching of Rigney, shooting of John Chinnick- mystery surrounding shooting- 3 rumors- suicide, jealous wife, vigilantes fearing him turning traitor- Vigilance committeee order number of people to leave town- roughs organized and ordered Vigilance committee to leave- determined citizens organized to save town- mob dispersed & town was quiet.
1883-8-24 Bismarck Tribune
John Chinnick late proprietor of Cosmopolitan theater Miles City, who was accidently shot at time of big fire & hanging of Bill Rigney, died Tuesday afternoon.
1884-3-16 Helena Independent
Calvin H. Lille and Mrs. Iola Chinnick of Miles City, were married few days ago. Bride is widow of John Chinnick who died last fall from effects of pistol wound about which there was some mystery at time.