Nasir missed the recent home series against Zimbabwe but returned to form in the domestic 50-over league.
All-rounder Soumya, 21, was chosen ahead of the experienced Imrul Kayes and Shamsur Rahman despite having played just a single one-day international so far.
“The return of Nasir will add depth in our batting,” chief selector Faruque Ahmed said.
“Soumya is a utility player who can bat at the top order and his medium pace bowling can be handy in Australia-New Zealand conditions.”
Paceman Taskin Ahmed also returns at the expense of Shafiul Islam. Sabbir Rahman and Taijul Islam, who both made their ODI debuts in the Zimbabwe series, were retained.
There was no room for veteran left-arm spinner Abdur Razzak, the country’s leading wicket-taker in ODIs with 207 wickets in 153 matches and their most successful bowler in the 50-over World Cup.
Arafat Sunny, who claimed eight wickets in his last two ODIs, was preferred over Razzak.
“Sunny is a seasoned campaigner who has been playing in top domestic tournaments for the last 10 years,” said Ahmed.
“But he did not get chances because of Razzak. Now he is in better form. Also, we thought Razzak’s fielding could be an issue.”
Paceman Mashrafe Mortaza continues as captain while star all-rounder Shakib Al Hasan will be his deputy.??
Bangladesh will play in Pool B alongside co-hosts Australia and New Zealand as well as England, Sri Lanka, Afghanistan and Scotland.
They will start their campaign on February 18 against Afghanistan at Canberra.
The World Cup 2015 will be staged from February 15 to March 29.
Squad: Mashrafe Mortaza (capt), Shakib Al Hasan, Tamim Iqbal, Anamul Haque, Mominul Haque, Mushfiqur Rahim, Mahmudullah, Nasir Hossain, Sabbir Rahman, Soumya Sarkar, Rubel Hossain, Taskin Ahmed, Al-Amin Hossain, Taijul Islam, Arafat Sunny.