Below is the list of all the new countries added by this mod: (Now separated by country!)

USSR:
ASK = Astrakhan
BIR = Birobidzhan
CHE = Chernigov
GUK = GreenUkraine
IUR = Idel-Ural
KRA = Krasnodar
ING = Ingria (Leningrad)
MOS = Moscow
MOU = Mountain
NOV = Novgorod
PRM = Perm
PLE = Polesia
PSK = Pskov
SIB = Siberia
SMO = Smolensk
VLG = Volga
STA = Stavropol
TAM = Tambov
TAR = Tatarstan
URA = Urals
WHS = WhiteSea

Germany:
BER = Brandenburg
HES = Hessen
WSP = Westphalia
OST = Ostpreussen
POM = Pommerania
RHI = Rhine


Italy:
LOM = Lombardy
NAP = Naples
PIE = Piedmont
RHO = Rhodes
RMN = Romagna
SAR = Sardinia
SIC = Sicily
TRS = Trieste
TUS = Tuscany
UMB = Umbria
VNI = Venice

France:
ALS = Alsace
BRG = Burgundy
CHP = Champagne
GAS = Gascony
LOR = Lorraine
NRM = Normandy
ORL = Orleans
PAS = Paris
PIC = Picardy
POI = Poitou
PRO = Provence
RAL = Alps
SAV = Savoy
PML = St. Pierre & Miquelon

Spain:
ARA = Aragon
ASU = Asturias
BAL = Balearic Islands
CAS = Castile
EXT = Extremadura
GRA = Granada
LEO = Leon
MUR = Murcia
VAL = Valencia

Britain:
CRN = Cornwall
EAN = East Anglia
GBR = Gibraltar
LBR = Labrador
LON = London
MRC = Mercia
NFL = Newfoundland
NRT = Northumbria
SUX = Sussex

Belgium:
FLA = Flanders
WAL = Wallonia

Netherlands:
BRB = Brabant
HLD = Holland
FRS = Friesland

Canada:
ALR = Alberta
BCU = British Columbia
CSC = Cascadia
MNI = Manitoba
NBR = New Brunswick
NVS = Nova Scotia
NWT = Nunatsiaq
NNV = Nunavut
ONT = Ontario
SKS = Saskatchewan
YUK = Yukon

United States:
ALK = Alaska
ARI = Arizona
CLF = California
SCS = Confederate States
DSR = Deseret
FLO = Florida
LOU = Louisiana
MRY = Maryland
NEE = New England
NJR = New Jersey
NMX = New Mexico
NYO = New York
OHO = Ohio
ORG = Oregon
PEN = Pennsylvania
TXS = Texas
WSH = Washington
TNS = Tennessee
ARK = Arkansas
ILL = Illinois
IND = Indiana
SCR = South Carolina

Denmark:
FIE = Faroe
GRN = Greenland

Ireland:
CNC = Connacht
LEI = Leinster
MUN = Munster

Portugal:
BJA = Beja
LIS = Lisbon
PRT = Porto

Austria:
TIR = Tyrol

Czechoslovakia:
BOH = Bohemia
CRP = Carpathia
CZC = Czech Republic
MRV = Moravia
SDT = Sudetenland

Sweden:
GOT = Gotland
SCN = Scania

Norway:
NRN = Nord-Nordge
TRD = Trondelag

Finland:
ALA = Aland

Latvia:
CRL = Courland
RGA = Riga

Lithuania:
MEM = Memel

Poland:
GAL = Galicia
KIL = Kielce
LUB = Lublin
MAZ = Mazovia
POZ = Poznan
LOD = Lodz
WTP = Pomerelia

Greece:
ATH = Athens
CNM = Central Macedonia
CRE = Crete
EPI = Epirus
PEL = Sparta/Peloponnese
THR = Thrace

Romania:
DBJ = Dobruja
MDV = Moldavia
WLC = Wallachia

Yugoslavia:
DAL = Dalmatia
SVN = Slavonia
VJV = Vojvodina

*Nordic Region:
LAP = Lapland


Also, there are the "Special Cases", to understand better what they are, go see the changelogs:

BAY = Bavaria (Germany)
BRI = Brittany (France)
CAT = Catalonia (Spain)
COR = Corsica (France)
HAW = Hawaii (USA)
MEK = Mecklenburg (Germany)
OCC = Occitania (France)
PRE = Prussia (Germany)
SAX = Saxony (Germany)
TRA = Transylvania (Romania)
ADU = Andulusia (Spain)
BSQ = Basque (Spain)
HAN = Hannover (basically replaced by westphalia)
SHL = Holstein (Germany)
ALT = Altai (USSR)
CRI = Crimea (USSR)
DAG = Dagestan (USSR)
DON = Don (USSR)
KAL = Kalmykia (USSR)
KAR = Karelia (USSR)
SIL = Silesia (Germany)
ESB = Far Eastern SSR (USSR)
PAP = Papal (Italy)
QUE = Quebec