Sharif was one of six regional leaders to attend the lavish inauguration on Monday evening for Modi, a former tea boy who has been elected leader of the world's largest democracy with the strongest mandate for 30 years.
Modi has an image as a hardliner, even within his own Hindu nationalist party, and is regarded with deep suspicion by many in Pakistan after deadly anti-Muslim riots erupted in his western fiefdom a decade ago.
But in a surprise move that disarmed many of his critics, Modi decided last week to invite Sharif to his inauguration and then to join him for bilateral talks scheduled for Tuesday morning.
"Let us together dream of a strong, developed and inclusive India that actively engages with the global community to strengthen the cause of world peace and development," Modi said as he was sworn in on Monday.
It will be the first time an Indian prime minister has hosted a Pakistani leader for official talks in New Delhi since the rupture in relations that followed the 2008 attacks in Mumbai when 166 people were killed.
The Mumbai killings were blamed on Lashkar-e-Taiba, a Pakistani militant group which is now accused of being behind an attack by gunmen last week on an Indian diplomatic mission in western Afghanistan.
"According to the information that we have available to us -- one given to us by a Western intelligence agency -- the perpetrators were of Lashkar-e-Taiba," the outgoing Afghan President Karzai, who is also due to meet with Modi, told Indian television on Monday.
- Strong mandate -
In an interview to India's NDTV network, Sharif said that Modi's arrival in power after a landslide election victory represented a "great opportunity" for the countries to open a new chapter in relations.
"This is a chance to reach out to each other. Both governments have a strong mandate," added Sharif who won Pakistan's election last year.
Sharif promised to pick up the threads of a failed peace process which went on during his second term in office -- coinciding with the last time Modi's Bharatiya Janata Party (BJP) was in power in India.
In 1999, then-Indian prime minister Atal Bihari Vajpayee rode a bus to the Pakistani city of Lahore to sign an accord with Sharif, but three months later the neighbours nearly went to war over Kashmir.
Sushma Swaraj, the most senior woman in the BJP, is expected to be named as foreign minister when Modi announces his government on Tuesday.
Although Modi has still to distribute the portfolios, he was one of 46 people who took the ministerial oath on Monday night -- 25 less than in the outgoing government headed by the left-leaning Congress party.The cull is part of a drive to speed up decision-making and slash India's notorious bureaucracy, blamed in part for a slowdown in the economy which is now growing at its lowest rate in a decade.
The job of finance minister is expected to be handed to Arun Jaitley, an urbane lawyer who has emerged as one of Modi's chief lieutenants.
Several television channels reported that Modi was likely to chair his first cabinet meeting on Tuesday evening in another signal of his desire to promptly set out clear targets for his government.
In a statement to mark his swearing-in, Modi said his election had handed him a mandate for "development, good governance and stability", avoiding any reference to the Hindu nationalist plank of the BJP's manifesto.
Modi, who rose through the ranks of right-wing Hindu organisations, is tainted by anti-Muslim riots that occurred while he was running his home state of western Gujarat in 2002 that killed at least 1,000 people.