I am currently reading Nehru's 'The Discovery of India' which is about Indian history as well as his experiences of Indian freedom struggle. I think you can download it legally from here.
Although he has substantially praised Buddhism in the book, that is equally true about Hinduism as well. Actually, what he seems to be interested in is the sociological implications of Buddhist and Hindu philosophies rather than the religions themselves.
From The Discovery of India, p. 26, about Nehru's personal beliefs.
Religion, as I saw it practised, and accepted even by thinking
minds, whether it was Hinduism or Islam or Buddhism or Christianity, did not attract me. It seemed to be closely associated
with superstitious practices and dogmatic beliefs, and behind it
lay a method of approach to life's problems which was certainly
not that of science. There was an element of magic about it, an
uncritical credulousness, a reliance on the supernatural.
Yet it was obvious that religion had supplied some deeply felt
inner need of human nature, and that the vast majority of
people all over the world could not do without some form of
religious belief. It had produced many fine types of men and
women, as well as bigoted, narrow-minded, cruel tyrants. It had
given a set of values to human life, and though some of these
values had no application to-day, or were even harmful, others
were still the foundation of morality and ethics.
About Buddhism from pages 130-131:
The Buddha story attracted me even in early boyhood, and I
was drawn to the young Siddhartha who, after many inner
struggles and pain and torment, was to develop into the Buddha.
When I visited countries where Buddhism is still a living and
dominant faith, I went to see the temples and the monasteries
and met monks and laymen, and tried to make out what
Buddhism had done to the people. ... There was much I did not like. The rational ethical doctrine had become overlaid with so much
verbiage, so much ceremonial, canon law, so much, in spite of
the Buddha, metaphysical doctrine and even magic. Despite Bud-
dha's warning, they had deified him, and his huge images, in
the temples and elsewhere, looked down upon me and I wondered what he would have thought.
But I saw much also that I liked. There was an atmosphere
of peaceful study and contemplation in some of the monasteries
and the schools attached to them. There was a look of peace
and calm on the faces of many of the monks, a dignity, a gentleness, an air of detachment and freedom from the cares of the
Finally, this paragraph, from p. 131 presents the conclusive evidence:
The pessimism of Buddhism did not fit in with my approach
to life, nor did the tendency to walk away from life and its problems. I was, somewhere at the back of my mind, a pagan with
a pagan's liking for the exuberance of life and nature, and not
very much averse to the conflicts that life provides. All that I had
experienced, all that I saw around me, painful and distressing as
it was, had not dulled that instinct.
Thus, I think it is fair to say that he was very much attracted to Hindu and Buddhist philosophies (one can find similar paragraphs about Hindu philosophies too), but he did not identify himself with any of the religions, certainly not with Buddhism.