Lokosa has been in terrific form in the Nigeria Professional Football League scoring 18 goals in 20 matches – including a brace against Katsina United on Sunday.
26-year-old Nwankwo gets his maiden international call-up thanks to his fine form in the Italian topflight where he has scored six goals in his last seven outings.
The Super Eagles are heading to their sixth World Cup, having taken part in the 1994, 1998, 2002, 2010 and 2014 editions – with a place in the Round of 16 their best performance ever.
Gernot Rohr has stuck with the quartet of Ikechukwu Ezenwa, Dele Ajiboye, Daniel Akpeyi and youngster Francis Uzoho in the goalkeeping department.
Regulars such as John Obi Mikel, Victor Moses, William Troost-Ekong and defensive partner Leon Balogun made the cut.
But missing from the 30-man selection released on Monday are Brown Ideye, Dele Alampasu, Anthony Nwakaeme, Henry Onyekuru, Victor Osimhen and Kayode Olanrewaju.
Nigeria begin their 2018 Fifa World Cup campaign against Croatia on June 16 at the Kaliningrad Stadium before facing Iceland (June 22) and Argentina (June 26) in Volgograd and Saint Petersburg respectively.
DEFENDERS: William Troost-Ekong (Bursaspor) Leon Balogun (Mainz 05) Olaoluwa Aina (Chelsea) Kenneth Omeruo (Kasimpasa) Bryan Idowu (Amkar Perm) Chidozie Awaziem (Nantes) Abdullahi Shehu (Bursaspor) Elderson Echiejile (Cercle Brugge) Tyronne Ebuehi (ADO Den Haag) Stephen Eze (Lokomotiv Plovdiv)
MIDFIELDERS: John Obi Mikel (Tianjin Teda) Ogenyi Onazi (Trabzonspor) John Ogu (Hapoel Beer Sheva) Wilfred Ndidi (Leicester City) Uche Agbo (Standard Liege) Oghenekaro Etebo (Las Palmas) Joel Obi (Torino) Mikel Agu (Bursaspor)
FORWARDS:Odion Ighalo (Changchun Yatai) Ahmed Musa (CSKA Moscow) Victor Moses (Chelsea) Alex Iwobi (Arsenal) Kelechi Iheanacho (Leicester City) Moses Simon (Gent) Junior Lokosa (Kano Pillars) Simeon Nwankwo (Crotone)