If kingdom means a country rules by a king (President or Prime Minister), then nation will be a tribe or group of people. So nation against nation will be civil unrests, protests, wars, rebellions, etc. caused by political, racial, tribal, religious, financial, etc. sources.
The series of demonstrations and protests across the Middle East and North Africa that commenced in December 2010, became known as the "Arab Spring. Within a short period of 3 months, almost all Muslim countries ( surrounding Israel) were involved in this 'Arab Spring':-
Tunisia Dec 18
Algeria Dec 29
Lebanon Jan 12
Jordan Jan 14
Mauritania Jan 17
Sudan Jan 17
Oman Jan 17
Yemen Jan 18
Saudi Jan 21
Egypt/Saudi Arabia Jan 25
Syria Jan 26
Djiboti Jan 28
Morocco Jan 30
Iraq Feb 10
Bahrain Feb 14
Iran Feb 14
Libya Feb 15
Kuwait Feb 18
(Many governments gave economic concessions, removal of some restrictions, etc. to ease problems.)
This 'Arab Spring' is the fulfillment of 'Rumours of nations rising against nations' whereby the public had expressed their dissatisfactions with their governments and their desires for change.
all these things must come to pass
The Arab Spring developed into the Arab Uprisings with civil wars and rebellions in many Arab countries. By the end of February 2012, rulers had been forced from power in Tunisia, Egypt and Libya; civil uprisings had erupted in Bahrain and Syria; major protests had broken out in Algeria, Iraq, Jordan, Kuwait, Morocco, and Sudan.
All these civil wars and rebellions were caused by the infighting between the various factions of Islam (Shia, Sunni and Wahhabi) fulfilling prophecy of 'Nation against nation'. Many of these countries settled their problems in various ways with some of the heads of States being sentenced to death or killed.
Libya suffered very badly during the revolution with its leader and some family's members killed mercilessly. Yemen is facing ruin with Saudi Arabia supporting the rebels. The authorities in the land of Syria and Iraq are still fighting ISIS a group of ultra extremists with mad killers.
but the end is not yet
This clearly states that some of these religious wars will be so intensive, cruel, extensive, etc. that those found there, will be living in hell as though it is the end of the world. This was the case found in Syria and Iraq.
When ISIS (Sunni Wahhabi extremists - former al Qaeda) took over a large part of the land and declared the Caliphate, they brutally murdered many non extremists including Shia, moderate Sunni Muslims and non-Muslims. Women were raped and sold as sex slaves.
All retaken towns in both Syria and Iraq were in complete ruins. Factories and oil fields were set on fire causing health hazards. Many of those wanting to flee were brutally killed. Civilians including women and children were used as human shields. Estimates that more than 25℅ of population killed.
Iraq and Syria are moving towards fulfilling end time Bible prophecies.