Of American-English origin, the noun talkaholic, also talkoholic, designates:
– a person who talks excessively;
– a person who is addicted to talk radio.

For example, this noun occurs as talkaholic in Podcasts: Pick of the week, published in The Guardian (London and Manchester, England) of Saturday 10^th September 2022 [Section GDN 1L: page 7, column 3]:

The Loudest Girl in the World
Widely available, episodes weekly
Self-confessed “talkaholic” Lauren Ober always found life a little harder than it should be, but a surprise diagnosis of autism during the pandemic explained why. In this podcast, she’s open about the anxiety and sensory issues that led to accusations of bad behaviour at school—and cruel, unfair punishments. Hannah Verdier

The noun talkaholic, also talkoholic, is from:
– the verb or the noun talk;
– the suffix ‑aholic, also -oholic, which is used to form nouns designating a person who is addicted to the thing, activity, etc., expressed by the first element—as in the noun shopaholic, designating a compulsive shopper.

The earliest occurrences that I have found of the noun talkaholic, also talkoholic, are as follows, in chronological order:

1-: From the column One Woman’s View, by Maude Johnson, published in The Bremerton Sun and The Daily News-Searchlight (Bremerton, Washington, USA) of Thursday 21^st January 1954 [Vol. 53, No. 249, page 18, column 2]:

Some Gabby Souls Overindulge

Unfortunates who imbibe too freely of alcoholic beverages have a parallel in the gabby souls whose over-indulgence consists rather in what goes OUT of the mouth. Psychologists refer to this unhappy state as “compulsive” chatter. These unfortunate victims babble on and on—easily led by companions who urge “just one more” topic of conversation.
The stimulant of having a good listener can lead sufferers to ignore appointments and to forget home and family. For their sakes perhaps we should establish a Talk-Aholics Anonymous. (Any charter members besides me?)

2-: From The Blabbermouths Of the Airways, by Dick Nolan, published in the San Francisco Examiner (San Francisco, California, USA) of Wednesday 13^th May 1964 [page 27, column 6]:

THOSE OF US in the public information trade hardly know whether to applaud or to weep bitter tears over the continuing craze in radio for those telephone talk shows.
[…]
They can become a habit, these gabfests. So far I only listen idly on my car radio, but I listen a lot. If I ever catch myself twiddling the home tuner to them, though, I’ll swear off. Who wants to become a talkoholic!

3-: From an advertisement for X·TRA/KŌST Radio 690 AM 103.5 FM, Los Angeles, California, published in the Los Angeles Times (Los Angeles, California, USA) of Friday 25^th December 1970 [Part IV: page 38, column 4]:

KABC Radio listeners
attention.
A special offer for talkaholics from X·TRA/KŌST.

Now right off, let us say that we (X·TRA/KŌST) think KABC is a fine radio station, shades of sun city—who knows, maybe even a great one. And we also know that they have a lot of listeners, and this is where our special offer comes in. X·TRA, 690 AM and KŌST, 103.5 FM are music stations. We are just about as opposite as you can get from KABC. […] Now we’re smart enough to know that if you have listened to talk radio for any length of time, you may have unwittingly become a talkaholic. Now we’re not suggesting you give up KABC cold turkey, but you will find that taking a music break from time to time will help maintain your sanity and in the long run, will probably keep you from talking to yourself.

4-: From In this Sunday’s News, published in the Daily News: New York’s Picture Newspaper (New York City, New York, USA) of Thursday 28^th December 1972 [Vol. 54, No. 160, page K3, column 4]:

JACK IS BACK
The guy who made late-night talk shows famous has, in his words, been talked into coming back to television. In an interesting home interview with Paar and his wife, Radio/TV Editor Kay Gardella provides a close look at a man she calls a “sometimes mawkish, but never dull talkaholic.” You’ll find this 3-page picture story in the Magazine section of the Sunday News.

5-: From As Jack was saying when he was interrupted…, by Kay Gardella, published in the Sunday News: New York’s Picture Newspaper (New York City, New York, USA) of Sunday 31^st December 1972 [Vol. 52, No. 35; New York News Coloroto Magazine]:

[page 11, column 1]: AFTER A 10-YEAR ABSTINENCE broken only by an occasional public bender, that usually witty, frequently waspish, sometimes mawkish but never dull talkaholic, Jack Paar, has fallen off the wagon.
He swore he’d never again succumb to his compulsion to verbalize before all those folks out there in television land, but for a man who feels that talking is the logical employment of breathing, his fall from silence is as understandable as it is forgivable.
[…]
[page 13, column 3]: We shall soon see what a decade of abstinence has done for our talkaholic, the Alexander Graham Bell of electronic conversation.