There's a discrepancy in how Nostradamus is perceived by non astrologers and how he's perceived by astrologers, I think.
With him getting much higher esteem by people who aren't versed in astrology.

I went through the English Wikipedia article, and wasn't able to find any conclusive proof that he was a well versed astrologer, even though he claimed to have studied the subject and his almanacs and quatrains were supposedly based on astrological predictive technique.
Like many practitioners of astrology, during his time, it seems that he was a well known apothecary and physician (even though he was expelled from his medicine studies in the University of Montpellier).

There's also this claim in the Wikipedia article, based on 3 sources:

[H]e generally expected his clients to supply the birth charts on which these would be based, rather than calculating them himself as a professional astrologer would have done. When obliged to attempt this himself on the basis of the published tables of the day, he frequently made errors and failed to adjust the figures for his clients' place or time of birth.

Is there something I'm missing?
Is there a source which gives Nostradamus credit, for his astrological 'know how'?
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If not, I think it would be safe to assume that Nostradamus wasn't a a serious astrologer and that his prophecies and almanacs were a mix of different divinatory methods, which probably included astrology, but did not relay solely on it. What some people call today a 'psychic'.

Astrology itself is mentioned only twice in Nostradamus's Preface and 41 times in the Centuries themselves, but more frequently in his dedicatory Letter to King Henry II. In the last quatrain of his sixth century he specifically attacks astrologers.
Many of his astrological references are taken almost word for word from Richard Roussat's Livre de l'estat et mutations des temps of 1549–50.
(Wikipedia)

"There was a legend that whoever drank from the skull of Nostradamus would inherit his incredible powers. But for 200 years his grave had remained undisturbed because the legend also said that whoever did so, would immediately die.
"One night, at the height of the French Revolution, three drunken soldiers set out to test the legend.

It was not the skeleton that suddenly sobered the soldiers, but the plaque around its neck, with the date: May 1791, which could only have been placed there at the time of burial in 1566, Nostradamus had predicted, 200 years before, the exact date when his body would be dug up."

Anyway one of the soldiers poured some wine into the skull and took a swig. As he did so, a shot rang out, and he dropped, dead as well as drunk.'"
(Nostradamus: His imagined life)
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For an astrologer we need to investigate 2 midpoints: Mercury/Uranus and Uranus/Apollon
Not much is happening under ME/UR in his chart but the UR/AP shows an interesting combination.
It is conjunct Neptune/Hades which relates to fraud and deception.
Nostradamus used drugs but he claimed they did not give him his visions, only enhanced his ability to see them. We also see the miscalculations of his charts and the copied references. (Neptune here).
The fact that he attacked astrologers in the last quatrain of his sixth century is a signature of Hades.

Another astrologer from the 16th century who attacked astrology was Kepler (also with Hades in the UR/AP picture) but obviously for different reasons, he knew how to calculate and tried to bring a more scientific view of this science.