They feel threatened?? They are already under NATO nuclear umbrella and had nukes stationed by USA
The US has 50 nuclear bombs stored in Turkey. As tensions rise between the two countries, a look at how they got there and what might happen next.
theconversation.com
Basically Soltan Padishah Erdogand wants to make Turkey an "independent power", not some random US vassal country like all the other NATO fellows and countries like Japaneez and Korea.
Getting Nukes is a stepping stone to that.
His g*ndmasti regarding S400 and letting F35 slip through his grasp and whatever indigenization programs Turkey has is also a part of this "paradigm" so to speak.
In NATO only Anglo and Frenchie were "allowed" to develop Nukes without much drama, for all other NATO walas and the aforementioned East Asian jodi it is explicitly prohibited, along with other US allies like Saudia.
ofc DA JOOS are their own masters so they have Schrodinger's nukes anyway hidden somewhere in Israel.